Captcha breaker freezing and SER getting stuck at 31 threads on windows 16

Since the 13.28 version of GSA ser , i have been getting this error in GSA ser  “Gsa Captcha Breaker: Please start search engine ranker as admin!”   and at the same time captcha breaker stops solving the captchas , freezes and sometimes error window comes up . Both ser, cb have been run as admin.

 This happens within few minutes of starting, running both SER, CB at over 200 threads OS is win2016, 64 bit, i7, 16 gb ram from Hetzner, contabo both german.
 

 SER gets stuck at 31 threads everytime and CB is frozen with/without error code. When this started happening CB bug report showed error that has something to do with  Invalid window handle, system error, error code 1400( checked it was something to do with multithreading). Error Screenshot attached, first appeared on 22-24 feb , it doesn’t come up that frequently  like it was but the problem is still the same.

Server was formatted , changed servers but still this is happening. There could be issue with one server but not 2 new server with fresh windows 2016 installations.

ser alone works fine with 2 captcha alone, 2 captcha setting was done in ser. CB was not started.

Catchall from different providers and real emails both are causing problems on over 200 threads. It is working fine with free emails created within ser  . Could this be german hosting blocking bulk email checking ?. Does it need some particular windows service ?

There is a Regularity like getting stuck at 31 threads everytime, problem happening when catchall, real emails are used, ser working fine with 2captcha. 

 
Sven looked in the server few days ago but couldn’t find a bug. 

Is anyone facing this when running windows 2016 ?