S o l u t i o n 
Anke found out, that you should never use special characters in your filenames!
It confused me a bit, because Android 10 did not have a problem with it.
Anyway, you should check your Android-Version, before you ask for permissions.
Anke made an extension for it.
I made it this way:
good luck out there and thanx to Anke again
Emanuel
Yes, colons (and some other special characters) were still allowed before the introduction of the Scoped Storage concept (i.e., before Android 11). Scoped Storage enforces stricter naming conventions and sets certain restrictions for filenames and paths. These prevent invalid or problematic characters that could lead to conflicts.
It may also be related to file systems such as FAT32 (often used on SD cards) or exFAT, which do not allow colons in filenames.
So, ultimately, you have no choice but to avoid such special characters if the app should also work on Android 11+.
These are exactly the blocks I already showed you.
Yes Anke. I used the blocks, you showed me. A perfect solution. You are great, Anke. Thank you, Thank you, Thank you. You are phantastic and I love you till the end of my days for it.
hugs and a bunch of kisses.
Emanuel
