That is my regular expression:
[A-Ö]{1}[a-ö]
When I write that everything is fine until I write another small letter it doesn\'t work. E.g.
Note that [A-Ö] matches all lower and uppercase letters and a lot of other symbols, too.
[A-Ö]
You need
[A-ZÖ][a-zö]+
See regex demo
Note that + matches 1 or more occurrences of the preceding subpattern.
+