Damaged masterkey and vault files

Suddenly my vault can’t be opened on Windows (nor iPhone).
vault.cryptomator and masterkey.cryptomator in the root directory seem to be damaged. I overwrote those files with bkup files that I found in the root directory and tried to open again. The follwowing error comes up:

Error Code 6PHE:B3EM:B3EM
org.cryptomator.cryptofs.VaultConfigLoadException: Failed to parse config: 

I tried password recovery but the recovery key was not recognized (Error: this key does not belong to this vault.).

Cryptomator version: 1.12.3 (msi-5219)
Password: I have it.
Recovery key: I have it.

Please someone help me open the vault…