Hello all,
Recently my Companion app will always auto closed it, even just few minutes after connected.
Is it my connection issue or something else? Is there any way for me to check?
Thanks. 
Without any further information it would be hard to give you good advise, it would be guess work.
Sorry for that.
The Companion app version is 2.68 which is same as in the https://ai2.appinventor.mit.edu.
And is not using legacy connection, and mostly connect using key in code.
Quite a few times after Companion connected to https://ai2.appinventor.mit.edu, then after around 1 or 2minutes it will auto disconnect.
Did you try using the legacy connection? Use it and tell is if the problem mitigates or goes away.
I tried legacy connection and it continues