Take note that you are comparing two different systems: Gmail and a router.
- Router's supported characters:
- a-z
- A-Z
- 0-9
- !@#$%&*^+-/=?_`{|}~.
- Gmail's supported characters:
As you can see, Gmail supports more characters (all ASCII), than RUT955. In this case simply change your Gmail's password, so that it would only contain characters which RUT955 supports.