@Rogart I see from the crt.sh history that you have issued Let's Encrypt certificates for ppctip.com and magicmama.de for a long time.
Is the problem you describe new? That is, has magicmama.de ever worked? If it did, when did the problem begin and what changed?
It would be unusual for your Apache to not support SNI but before even checking the Apache error log about that it would generally be helpful to understand the overall situation better. I think Rudy would appreciate it too. Thanks