Error when I create a new Metadata field

Problem

When trying to save a new metadata field (in a space or globally), the error "Title must be unique and must contain at least one character. Please choose another title." is displayed.

Solution

Special characters will be deleted when generating the key for the metadata field. This may lead to the same metadata key for fields with different titles. Please re-name your field in such away that it will not duplicate an existing field when removing all spaces, -, ., *, ä, ö, ü, ß, $ etc.