Where/how does this message show up?
Lately, i have come across this error message, “Disallowed Key Character” when i login into some of my article directories or when i login to other software tools. Because of this, i cannot proceed with any action. Even in one, i ws logged out, i was denied access, and i am requested to create an account. I tried to Google the issue but did not come across any concrete action which would help me to solve.
I have read about this happening do to a cookie having a $ character in it. You might try deleting your cookies or at least the one(s) related to the site(s) you are having trouble with.
Douglas County Master Gardeners
"People will forget what you said, people will forget what you did, but people will never forget how you made them feel."
Try clearing your browser's cache and delete all temporary Internet files.