I'm making an http request with a header containing user info (there is a different workflow before this and that's related to why the userInfo is in the header rather than the body). It has been working without any problems as long as the user info does not have any special characters (firstname, lastname) Eg. Oršulić. Any special characters in the header returns this error - Invalid character in header content ["tokenInfo"]

Is there a way to pass this information through. I own both the services making the request and the service handling it. Is there a way to encode the special characters to ASCII and convert them back?