Receiving the error “Disallowed Key Characters” when you load a page in codeigniter?
This error for me was caused by developing locally on my machine (127.0.0.1) with xampp and with my setup I used the windows host file to re-direct a subdomain sub.example.com for example to my local web server for development. However the problem then occured when I switched to developing online, I removed the host file entry for the sub domain and then received this error.
To solve the problem I had to clear my cookies, I believe it was a cookie session problem as when I also changed the unique encryption_key in the config file it also solved the issue.