German letters "ü"," ä", "ö", "ß"


my databases are in German. German letters “ü”," ä", “ö”, "ß"are displayed incorrectly or with question marks. Can you please tell me how this can be eliminated?
Thank you

Hi alex2000,

Sorry, but we haven’t faced it before. Could you please let us know if the backups are performed correctly in spite of this issue?

Sorry for the inconvenience.