App inventor BLE error:Connection status was set to OS code 133

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BLE connection failure esp32 Arduino 10

Thank you for your fast answer, it really help me solving the problem. First I implemented all your recommendations in app inventor application. That did not change anything to the problem but I will keep them in my final app as "best practices". Next, I thought about your comment on the MTU size. On the ESP32 code, I changed the "advertizing" long name (19 ascii bytes) to fairly short name (3 char). Connection is now successfull both on the small Arduino IDE demo app as well as my quite large…

If that doesn't help, export and upload your .aia and your sketch.