Maybe you should try removing the extension, and uploading it again
But i need the extension in order to communicate with my arduino BLE
Yes I know, just try to remove the extension and upload again.
Removed it , no issues at all just cant connect or do anything , only text assigned to button changes value .
Without extension i dont have issues other than my app is useless 
got it
Its the last brick to finalize my project 
I ll try it but i dont understand anything , do i download aix file ?
yes 
thnx i ll give it a try
problem with this extension , is there is no module to receive data .
why you don't use the existing bluetooth server directly in the mit app inventor
because it wasnt reading my BLE , i wanna connect it with arduinoBLE
Okay i got it, please see this :
Error from Companion: java.lang.NoClassDefFoundError: edu.mit.appinventor.ble.BluetoothLEint$1
Same error when i open it . i followed all the steps
As far as I know, you cannot use extensions on iOS yet, if ever, therefore no BLE. Therefore you should try this on an Android phone.
And definitely install the AI Companion on that Android phone. It will help you enormously in debugging.
I looked into your .aia - what I see is that you never connect to your BLE device, so, what you have can never work. Start with the basics, do some tutorials: http://appinventor.mit.edu/explore/ai2/tutorials
or here: http://iot.appinventor.mit.edu/#/getstarted/intro
I am not familiar with thingspeak, so maybe you can explain how you plan to interface with it and why do you need both a webviewer and a BLE connection.
p.s I find your username offensive, I think you should change it. If you don't I may block you.
p.p.s. @Salman_Dev I know that you are trying to be helpful, but it would help if you would research your answers a bit better.
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Usually this error occurs if your phone is too old. The BLE extension uses APIs that aren't available until Android 5.0. On earlier versions, the class will not link correctly due to the missing dependencies, resulting in a NoClassDefFoundError.
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An 'old' Android phone may not be compatible with BLE or the BLE Extension (Minimum Android v5.0 Lollipop required), but that is not necessarily causing your issue. Does your Project include images? In particular, a custom image for the App Icon? The problem may stem from there.
See my website for a list of possible causes:
ProfessorCad: Tips & Tricks Cannot Build/Install/Run APK
ProfessorCad: Tips & Tricks
ProfessorCad: Tips & Tricks
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Assuming your Android phone is new enough to run BLE, your Project 'ecg_rose' has an old BLE Extension. It should be version 20200828.
- How did you obtain the UUIDs? They need to be 100% correct.
- You may also need to give the phone time to list all available BLE Devices, currently the App expects the list to be built immediately on tapping Button4.
- Google Locate must be switched on (as must Bluetooth).
- You are receiving Integers into a text Block? I think we need to see your Arduino Sketch - you can upload it to your Forum Topic as a .txt file.