Square Reader pairs but can't establish a secure connection to Square (Mobile Payments SDK iOS 2.5.0, production, Australia)

Questions
1

Hi team,

I’m integrating the Mobile Payments SDK into an iPad app for a photo booth
business here in Australia and I’m stuck on a reader connection issue I
can’t resolve from my side.

The reader pairs over Bluetooth without any trouble, but it then sits
permanently unavailable with “Unable to establish a secure connection to
Square”. This has been 100% reproducible for two days.

Setup details:

  • Production Application ID: sq0idp-HOLl6KeSX5NL2eVGT2mqww
  • Bundle ID: au.appnerd.PhotoboothWoodRemote
  • Team ID: R8V696537A
  • Application signature registered 8 Jul 2026. I’ve verified with codesign
    that the Identifier and TeamIdentifier on the actual built binary match
    the registered signature exactly.
  • SDK 2.5.0 via Swift Package Manager. initialize() runs in
    didFinishLaunchingWithOptions and authorization succeeds (state is
    .authorized). OAuth token scopes: MERCHANT_PROFILE_READ, PAYMENTS_WRITE,
    PAYMENTS_WRITE_IN_PERSON.
  • Merchant: Australian account
  • Reader: Square Reader contactless and chip

The part that convinces me this isn’t a device or network problem: Square
Point of Sale on the exact same iPad connects this same reader and reaches
Ready immediately. The iPad is on the latest stable iPadOS with no VPN,
proxy or management profiles. The failure only happens through my MPSDK app.

Things I’ve already tried: registering the signature (and deleting and
re-adding it), deleting and reinstalling the app, power cycling the reader
and re-pairing multiple times, forgetting the reader from POS between
tests, and many hours of retries.

Could you please check your backend logs for the secure session rejection
reason for this application ID and reader serial around that timestamp?
I’ve run out of things I can verify from my end.

Thanks,
Alex

2

Thanks for the detailed write-up- really helpful! How is the app being installed on the iPad? Running directly from Xcode, via TestFlight, or from the App Store? We’re investigating in parallel on our side.

3

Hi Ashley, Thanks so much for your prompt reply. We’ve tried it through Xcode and Testflight with no success.

4

Since the reader works with Square POS on the same iPad, it does sound like the hardware and network are fine. At this point, I’d open a developer support ticket with the timestamps, reader serial, and your Application ID so the Square team can check their backend logs for the secure session failure. It may be an account, app registration, or backend provisioning issue that isn’t visible from the SDK side.

5

We are currently working on a fix for this issue.

6

Same issue here:

Setup details:

* Production Application ID: sq0idp-6AUlVUtAZT0rPJoUOp4dtQ

* Bundle ID: com.matchabar.kiosk

* Team ID: W694RA45K4

* Application signature registered in the Developer Console (Bundle ID

com.matchabar.kiosk / Team ID W694RA45K4)

* SDK 2.5.0 via Swift Package Manager

( GitHub - square/mobile-payments-sdk-ios: Public repository that hosts the Square Mobile Payments SDK iOS binaries · GitHub , exact version 2.5.0).

initialize(applicationLaunchOptions:squareApplicationID:) runs in

didFinishLaunchingWithOptions; authorization succeeds (state is

.authorized). Location + Bluetooth permissions are resolved before

authorize is called.

* OAuth token scopes: MERCHANT_PROFILE_READ, PAYMENTS_READ,

PAYMENTS_WRITE, PAYMENTS_WRITE_IN_PERSON,

DEVICE_CREDENTIAL_MANAGEMENT, ORDERS_WRITE, ORDERS_READ, ITEMS_READ

* Distribution: TestFlight (production credentials)

* Merchant: UK account

* Reader: Square Reader (2nd gen) contactless + chip, Square Stand 2nd gen (lightning)

Symptom:

Reader pairs and reaches ready on first pairing. After an app restart the

reader returns readerUnavailable with secureConnectionToSquareFailure

(“Unable to establish a secure connection to Square”) and never recovers;

only forget + re-pair restores it. retryConnection() and a programmatic

rebootReader() do not resolve it.

Device-specific: the failure reproduces consistently on an iPad 9th gen

(Bluetooth 4.2, freshly restored) and does NOT occur on

an iPad Pro 11" 1st gen (Bluetooth 5.0) — same build,

same account, same reader. On the Pro the pairing survives app restarts

and full iPad reboots.