Still No log ..What should I do to fix it?
Do you have any old/spare Android phones nearby? Or friends or family with an old/spare phone? You do NOT need a working a SIM phone account. Usually don't even need a SIM in the phone.
Or: can you buy a cheap prepaid phone at a local shop? Here in Australia, I have regularly picked up phones for under $30 (EUR 20). They have small screens (well... 4") and are locked to a network, but for the purpose of B4A development, this is no problem (unless your app is something to do with phone functions, I guess).
A last resort is to install B4A-Bridge on a friend/family phone and run a short app that generates some logs, just to confirm that the issue is something to do with the phone. Problem with doing this is: everything that evermore goes wrong with that phone will be your fault ;-)
Also, it won't fix the log problem with your original phone, but it does give confidence that the B4A setup is still working, and thus not to give up.
I still have not worked out precisely what triggers the issue, or fixes it, but so far it has eventually righted itself. I understand that it is mighty irritating the way it happens just when you need logs the most, though, so...
I feel your pain.