New OS5 - Drobo 5C connected via USB port not working

Hello, since OS5 upgrade i can’t copy files to my Drobo 5C connected via USB port, things where fine before, when i try to copy one file the system stops, the only solution is to shutdown the drobo, i tried with an external drive and it works fine, slow speeds but fine.
any help would be much appretiated.

You many need some new firmware on your Drobo and seems that StorCentric now own them ?

Version 4.2.1 [11.67.115458] from 5 Nov 2020 is all I can find.