# Cannot Connect Square reader using mobile payments sdk **URL:** \ **Category:** Questions\ **Created:** [May 17, 2026, 6:19am UTC](https://developer.squareup.com/forums/t/cannot-connect-square-reader-using-mobile-payments-sdk/26122 "2026-05-17T06:19:15Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![anikal2001](https://avatars.discourse-cdn.com/v4/letter/a/cdc98d/32.png) [@anikal2001](https://developer.squareup.com/forums/u/anikal2001)\ **Post date:** [May 17, 2026, 6:19am UTC](https://developer.squareup.com/forums/t/cannot-connect-square-reader-using-mobile-payments-sdk/26122/1 "2026-05-17T06:19:15Z")
I have implemented the ios react native plugin for the Square Mobile Payment SDK and am currently using a production App ID. While attempting to connect the Square Reader through the Square settings screen, I receive a **“Reader pairing successful”** message; however, it is followed by the error: **“Reader unavailable: Unable to establish a secure connection to Square.”** From my end, I have already: - Updated the app signature (SHA-256) on the Square Dashboard - Activated the Square account I didnt modify the sdk in anyway. This happened 2:24 AM (05/17/26). Could you please confirm if any additional setup or configuration is required to resolve this issue? Timezone: EST App ID: sq0idp-PmI6CXKFXkfoou5Q22JIDg Location Id: L0P18VSSEXCYV SDK Version: 2.5.0 ---
**Author:** ![Square-Dev-AI](https://sea1.discourse-cdn.com/square/forums/user_avatar/developer.squareup.com/square-dev-ai/32/2513_2.png) [@Square-Dev-AI](https://developer.squareup.com/forums/u/Square-Dev-AI)\ **Post date:** [May 17, 2026, 6:19am UTC](https://developer.squareup.com/forums/t/cannot-connect-square-reader-using-mobile-payments-sdk/26122/2 "2026-05-17T06:19:25Z")
👋 I’m Square Dev AI, here to help answer your question! Based on the information you’ve provided, the following documentation will help answer your question: [https://developer.squareup.com/docs/reader-sdk/react-native](https://developer.squareup.com/docs/reader-sdk/react-native) [https://developer.squareup.com/docs/reader-sdk/cookbook/contactless-reader](https://developer.squareup.com/docs/reader-sdk/cookbook/contactless-reader) > **Additional Documentation** > > [https://developer.squareup.com/docs/reader-sdk/build-on-ios](https://developer.squareup.com/docs/reader-sdk/build-on-ios) > [https://developer.squareup.com/docs/reader-sdk/cookbook/square-stand](https://developer.squareup.com/docs/reader-sdk/cookbook/square-stand) > [https://developer.squareup.com/docs/reader-sdk/quick-start/step-2](https://developer.squareup.com/docs/reader-sdk/quick-start/step-2) If this documentation helped you find a solution, please check the box indicating that this reply solves the problem. Otherwise one of our Developer Advocates will provide additional assistance shortly. ---
**Author:** ![josh-square](https://avatars.discourse-cdn.com/v4/letter/j/77aa72/32.png) [@josh-square](https://developer.squareup.com/forums/u/josh-square)\ **Post date:** [May 18, 2026, 8:18pm UTC](https://developer.squareup.com/forums/t/cannot-connect-square-reader-using-mobile-payments-sdk/26122/3 "2026-05-18T20:18:33Z")
@anikal2001 Thanks for providing all those details here! I’ve escalated this to the team. ---
**Author:** ![josh-square](https://avatars.discourse-cdn.com/v4/letter/j/77aa72/32.png) [@josh-square](https://developer.squareup.com/forums/u/josh-square)\ **Post date:** [May 18, 2026, 9:44pm UTC](https://developer.squareup.com/forums/t/cannot-connect-square-reader-using-mobile-payments-sdk/26122/4 "2026-05-18T21:44:28Z")
@anikal2001 Are you able to verify that you have the correct app signature for the build you have installed? ---
**Author:** ![anikal2001](https://avatars.discourse-cdn.com/v4/letter/a/cdc98d/32.png) [@anikal2001](https://developer.squareup.com/forums/u/anikal2001)\ **Post date:** [May 19, 2026, 5:36pm UTC](https://developer.squareup.com/forums/t/cannot-connect-square-reader-using-mobile-payments-sdk/26122/5 "2026-05-19T17:36:01Z")
> [@josh-square](#): > > Are you able to verify that you have the correct app signature for the build you have installed? Yes, i believe the app signature is correct ---
**Author:** ![josh-square](https://avatars.discourse-cdn.com/v4/letter/j/77aa72/32.png) [@josh-square](https://developer.squareup.com/forums/u/josh-square)\ **Post date:** [May 20, 2026, 9:12pm UTC](https://developer.squareup.com/forums/t/cannot-connect-square-reader-using-mobile-payments-sdk/26122/6 "2026-05-20T21:12:32Z")
@anikal2001 The behavior you’re seeing really only happens when there’s an issue with the app signature. For context, it’s possible for each build you generate to have a different app signature, so you’ll need to make sure that your app signature being generated is the same across all debug and release builds. To troubleshoot, I’d recommend: 1. Try to get the app signature from an APK. 2. Make sure that app signature matches what’s in your developer console. 3. Try to install that APK and see if your error still persists ---
**Author:** ![anikal2001](https://avatars.discourse-cdn.com/v4/letter/a/cdc98d/32.png) [@anikal2001](https://developer.squareup.com/forums/u/anikal2001)\ **Post date:** [May 21, 2026, 3:50pm UTC](https://developer.squareup.com/forums/t/cannot-connect-square-reader-using-mobile-payments-sdk/26122/7 "2026-05-21T15:50:17Z")
I am building an IOS app ---
**Author:** ![josh-square](https://avatars.discourse-cdn.com/v4/letter/j/77aa72/32.png) [@josh-square](https://developer.squareup.com/forums/u/josh-square)\ **Post date:** [May 28, 2026, 8:16pm UTC](https://developer.squareup.com/forums/t/cannot-connect-square-reader-using-mobile-payments-sdk/26122/8 "2026-05-28T20:16:30Z")
Hey @anikal2001, we had a similar report for this issue (on both iOS and Android) here: > [@Cannot Connect Square Reader using Mobile Payments SDK \[Unable to Establish a Secure Connection to Square\]](https://developer.squareup.com/forums/t/cannot-connect-square-reader-using-mobile-payments-sdk-unable-to-establish-a-secure-connection-to-square/26146/4): > > For those facing the same issue, we have resolved it and it looks like Square Support is on the ball with this one. It just takes a little bit of fine toothing to make sure all the credentials are in the right place. Alright, for iOS, many of us in the past have used older Bundle IDs’ and this has been fine but with (I assume) recent updates to the SDK’s, the Bundle ID for both Android and iOS must be what is on the App Stores. They will usually match if you are using React Native. Ensure that … Can you take a look to see if that helps for your case as well?