As you can use the MANAGER 2 on the CM-50 (using the PC I hope), let’s first try to recover the firmware of the CM-50, maybe it got corrupted somehow, see this link
Once that is done you can try to download the (Play700_Task_EN. tskx) to the CM-50 again and see. The TSKX file can be downloaded to the CM-50 via TASK 3 or TASK 2 from the PC. From my experience on my PC, I can only download this file PROPERLY via TASK 2. When I used TASK 3, the code started to download but it never finished properly, for some reasons.
Once this code is downloaded properly to the CM-50, at runtime it should connect to the Android App properly. If something does not work properly at this point, it is very likely having something to do with the BT connection. On my own Android Tablet, I had found that I have to make sure that the App was actually connected/paired to the BT on the CM-50 EVERY TIME that I used that APP. Sometimes, it was the Android OS that “forgot” about that BT connection (I am no expert on Android OS, so I don’t know why) - so I had to make Android re-search and re-pair with it again before using the PLAY700 App. Yeah, there is a chain of communications links that need to be all connected together properly before the App works OK with the CM-50.
Another simple thing to check out too. When the CM-50 batteries are low, its BT receiver is the first thing to flake out.