Crash of Dektop and Android

Delta Chat version
Dektop: 1.2.0
Android: 1.3.0

Used DC without problems for like 3 Month then this happens.
On Windows Dektop: I did not get new messages (but I could send). CPU load was always at 15% in idle. Was not able to generate a Backup or export keys (File was not created).
Android: Could open the app but instant freeze on every click anywhere (even settings button)

To export keys I imported an older backup in Flightmode (online it graped all the new messages and freeze again) and the exported the keys to read messages I’ve got in thunderbird.

I set up the dektop and android again (imported the old keys…) but even without showing the old messages I got the freeze again after about 30min. So I deleted all messages (About 2k+) in the DC Mail folder (They are still in the Trash folder so I don’t think it was a space problem) and apps are working again, even without new installation on Android and with new installation on dektop.

I’ve send an App bugreport with Android (could not get a log file because of freeze)
My Dektop Logfile is here:
2020-04-24-13-56-41.log.txt (119.2 KB)
There are many reconnects but this was the case all the time (so not related to that) due to the config of the exchange server.