Troubleshooting

A payment or refund shows Result unknown

1. Open History, filter by Needs attention and open the original payment or refund.
2. Tap Check result again. For a terminal, the app asks it for that transaction's outcome.
3. If the result is still unknown, find the payment in Customer Area › Payments › Payment list by reference, time and amount. Decide what to do only after checking.

A crash or restart leaves the interrupted operation in History as unknown. Do not clear the app's data to remove it.

With Tap to Pay, the Payments app cannot be asked for a status. Check result again uses only a late answer that has already arrived. If there is none, check the Customer Area before charging again.

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A payment is declined or not processed

The result screen shows the status, Adyen's reason and advice. Follow the advice:

“Do not retry with this card. Ask the shopper for a different card or payment method.”

CauseThe card issuer refused this card for a reason that will not change, such as a blocked or restricted card or suspected fraud, or the card is not allowed for this payment.

FixAsk for another card or payment method. The customer's bank can explain the refusal; the Adyen refusal reasons explain the reason shown.

“You can try again.”

CauseThe payment was canceled, the PIN was wrong, or the card was refused for a reason that may not repeat, such as insufficient funds.

FixTap Try again, or ask for another card.

“The terminal is busy with another transaction or its admin menu.”

CauseThe terminal is handling another payment or showing its admin menu.

FixFinish the other payment or leave the menu, then try again. If the screen offers Cancel the terminal’s current transaction, use it only to stop that transaction, and check its result before retrying.

“The terminal is not available right now.”

CauseThe terminal or its card reader is temporarily unavailable.

FixWait a moment, check that the terminal is on and connected, then try again. See network dropouts.

“The terminal did not accept the request. Check the Terminal settings before trying again.”

CauseThe terminal rejected the request or does not offer this service, usually because of a setup or account configuration problem.

FixRun the tests in Settings › Terminal; see pairing and setup. If they pass, ask Adyen to check the terminal's configuration.

“Do not charge again: this payment went through.”

CauseThe payment was approved even though the terminal reported a cancellation.

FixDo not charge again. Refund it if the customer should not pay.

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Scan wallet is missing or scanning fails

No Scan wallet button

Open Settings › Terminal and tap Refresh scanned wallets. A successful check with no eligible POS wallets leaves the button hidden. Check the assigned store, current currency and optional discovery role. Tap to Pay and pre-authorizations do not offer this action.

Wallet discovery reports an error

The error appears only in Settings and does not block ordinary payments. Fix credential/environment or read access problems there. A temporary refresh failure keeps the last verified list for unchanged setup; a successful empty check or access failure removes it. Configuration is checked at startup/setup changes and manual refresh, not before every sale.

The code is invalid or no code arrives

Use the shopper’s payment code, not a profile, transfer or receipt QR. Choose the correct wallet. Native scanning ends after 30 seconds: tap Scan again or Use camera. Allow camera permission when requested. Returning from the background requires a new scan.

Saving is rejected or no token is created

Follow the payment’s result. An approved payment stays approved without a saved token. Only after a conclusive rejection, return to checkout, turn off Save card and explicitly start another scan if appropriate. There is no automatic replacement payment. For Result unknown, check the original transaction instead.

PayMe scanning is rejected

PayMe merchant scanning is best-effort and conflicts with Adyen’s published limitation. Ask for another payment method or use the terminal’s normal wallet flow; do not treat a simulator approval as provider support.

See the wallet payment procedure. History’s requested wallet is intent, not proof that payment succeeded or that Adyen used that method.

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Pairing or setup fails

Start with the message on Home, then open Settings › Terminal and run Test API. For a physical terminal, also run Test connection. For Tap to Pay, check Payments app registration instead. For the full steps, see Connect to Adyen.

Home asks you to enter a detail “in Terminal settings”

CauseA required field is empty, or a saved key could not be read on this device.

FixEnter the missing detail, or enter the key again, in Settings › Terminal.

The API test fails or setup reports an access problem

CauseThe API key, merchant account or live URL prefix is wrong, a role is missing, or the credential is from another company account or environment.

FixCheck the credential's roles and access against the credential requirements. For LIVE, check the Live URL prefix.

“The merchant account does not match this terminal’s current assignment.”

CauseThe terminal is assigned to a different merchant account at Adyen.

FixEnter the merchant account that the terminal is assigned to, or reassign the terminal in the Customer Area.

The connection test fails on an Adyen terminal or network terminal

CauseThe shared key does not match, or the IP address or Terminal ID (POIID) is out of date.

FixCompare the shared key's identifier, passphrase and version with the Customer Area. For a network terminal, check the IP address and POIID on the terminal's Device info screen.

The connection is rejected because of the environment

CauseTEST and LIVE are mixed: the terminal, account and API key must all be from one environment.

FixFor a network or cloud terminal, check Environment in Settings › Terminal. On an Adyen terminal or with Tap to Pay, use a device or Payments app from the right environment.

A cloud terminal cannot be reached

CauseThe terminal is offline, the POIID is wrong, or the API key lacks the Cloud Device API role.

FixCheck that the terminal is on and online, then check the POIID and the credential's roles.

“Both the TEST and the LIVE Adyen Payments app are installed”

CauseTap to Pay needs exactly one Payments app.

FixUninstall the one you do not use. Then finish registration and enter the shared key. A successful setup check does not test a card payment; make a TEST payment.

“The new key is saved. Update this terminal’s config”

CauseThe encryption key was created at Adyen, but the terminal has not loaded it yet.

FixOn the terminal, open Admin menu › Config › Update, then return to Mini mPOS and tap Check again. If creation was interrupted, tap Resume key setup; it does not create a second key. See key creation and the Adyen configuration update guide.

Actions on an older payment are blocked

CauseThe merchant account, environment or terminal changed after that payment.

FixRestore the setup that took the payment, or handle it in the Customer Area. Do not process it under another account.

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The connection drops or the terminal does not answer

“The terminal did not answer”, or a network terminal works only sometimes

CauseThe terminal's IP address changed, the device moved to another network, or the network blocks the connection.

Fix

1. Check the terminal's IP address on its Device info screen and update it in Settings › Terminal.
2. Connect the device and terminal to the same network. Avoid guest Wi-Fi, which often isolates devices.
3. Ask the network administrator to allow TCP 8443 between them and to reserve the terminal's IP address; see network requirements.

Payments or API tests fail on every setup

CauseThe device or terminal has no internet access, or a firewall blocks Adyen.

FixCheck the internet connection, then make sure HTTPS on TCP 443 to Adyen's domains is allowed.

Cloud payments time out

CauseThe terminal lost its internet connection.

FixCheck the terminal's Wi-Fi, Ethernet or mobile data, then run Test connection.

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A capture or adjustment failed or is unknown

Open the original entry in History and read its reason. If Checkout API setup is missing, complete it; if the account or environment changed, restore the original one.

Capture failed or Capture result unknown

FixTap Retry capture. It resends the same capture safely; do not create a new payment.

An amount adjustment is unresolved

FixRetry with the same amount. A different amount is a separate request and may be blocked until the first is resolved.

A tip was not saved

CauseThe card issuer refused to increase the hold for a tip over 20%.

FixEnter a smaller tip, or tap No tip.

Capture requested or Refund requested does not change

CauseThese mean Adyen accepted the request. Mini mPOS has no server, so it never receives the final confirmation.

FixCheck the final outcome in the Customer Area.

Holds expire, so resolve these promptly. For the normal steps, see deposits and tips on the receipt.

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Payment links are missing or not updating

Checkout has no Create payment link

CauseCheckout API setup is incomplete, or the checkout is for a pre-authorization or a tip on the receipt.

FixComplete Checkout API setup in Settings › Terminal. Links are offered for sales only. For offline demos, see payment links.

A paid link still shows Awaiting payment

CauseThe app checks only while the link screen is open.

FixOpen the entry in History and tap Check payment.

Creating a link was interrupted

FixOpen the original entry and tap Check payment. It retries with the original request; do not create another sale just to get a link.

Refund paid links in Customer Area › Payments › Payment list.

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The printer or email receipts do not work

Nothing prints, or Print receipt is missing

CauseThe terminal has no printer, the printer was not detected, or the connection is down. AMS1 terminals and Tap to Pay phones have no printer.

Fix

1. In Settings › About, check that Printer shows Available. If not, run Test connection in Settings › Terminal.
2. In Settings › Receipts, set Printer to Detect automatically and check Print automatically after payment.
3. Tap Print test receipt. If nothing prints, check the terminal's paper roll.

The layout is cut off or wraps badly

FixChange Characters per line in Settings › Receipts and print a test receipt.

The test email fails

CauseWrong server, port, security or password, or the provider blocks SMTP or password login.

FixIn Settings › Email (SMTP), check the server, port, STARTTLS or SSL/TLS, username and password. Your provider may require SMTP access to be turned on or an app password; see email setup.

Test emails work, but customers get no receipt

FixIn Settings › Payments › Email receipts, check when the email is asked for and whether receipts are sent automatically.

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PIN and setup transfer problems

Staff forgot the Manager PIN

FixAn administrator can replace or remove it in Settings › Security. The admin PIN and Manager PIN protect different actions; one does not unlock the other.

The admin PIN is forgotten

CauseThere is no PIN recovery.

FixThe only way is to clear the app's data in Android.

Warning

Clearing the app's data deletes all products, settings, keys and payment history on the device. Resolve unfinished payments and keep the records you need first. A setup transfer does not restore history.

The transfer code is rejected, or keys are missing after import

CauseThe code does not belong to these QR codes, or it was left blank.

FixUse the code shown with these QR codes, not a newly generated one. Every transfer needs its code. A wrong or blank code imports nothing. After copying, check the destination and credentials on the new device; see more devices.

To review which actions each PIN protects, see staff PINs.

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The app does not install on a terminal

INSTALL_PARSE_FAILED_NO_CERTIFICATES

CauseThe APK is unsigned.

FixUpload the signed minimpos-<version>.apk from the latest release.

INVALID_SIGNING_CERTIFICATE_MISMATCH

CauseThe APK is signed with a different key from earlier uploads.

FixKeep the original signing source. If you need to change it, ask Adyen Support about removing earlier versions.

The Android version is not supported

CauseMini mPOS needs Android 9 or later; the older S1E runs Android 7.1.

FixUse a supported terminal; see installation.

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Still need help?

For Adyen accounts, terminal deployment, payment methods or final payment outcomes, contact Adyen. For an app problem, open a GitHub issue with the app version, device model, setup, TEST or LIVE environment and the steps to reproduce.

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