Diagnosis
You used a character that does not belong to the inventory of validcharacters, such as

• Umlauts ("ä", "ö", "ü", "Ä", "Ö", "Ü")


• The character "ß"


• Characters with diacritics (for example "á")


• Characters, which are no numerals or letters (for example "\", "-" or
"+")

Procedure
Replace the invalid characters with a valid character.