I get a "critical error" message when trying to create a folder in a subfolder in cryptomator

Hi there, this is my first post, so please forgive me mistakes or rulebreaks.
I get an error message when trying to create a folder in a predecessing folder.

Now before I get to the error itself, its worth mentioning that in other Folders that are contained in the same predecessing folder, its no issue at all to create a folder.. with the same permissions, even larger folder name.
Error message says translated to english something as follows: Error 0x8000FFFF: critical error
Couldnt find a matching fix so far, so im trying here.

Has anyone ever had something similar ocurring and is willing to help me :sob:?
Tysm in advance.