Donation error on ROC Server

[TMmivhi]

Hi guys
a few days ago we found a problem with the donation button on our Roc Server, see SShot.
Unfortunately, it is not possible to donate.
You get this error message.
"Transaction failed: Error: Internal error"

Currently Installed Server Version v2019-02-27_22_00 (3.3.0). Mode is: Rounds v2018-03-08 and Uaseco version 0.9.7 build 2019-003-12.

Maybe someone has an idea what it could be?

[undef.de]

FYI: We tested the functionality of the donate and payment function of UASECO on my development server and there it was working fine. So it's not a UASECO problem (I guess). Anyway, I never saw that error message before.