I had issue of @ which I added in $config['permitted_uri_chars'] as you can see below:
$config['permitted_uri_chars'] = 'a-z 0-9~%.:_@\-';
BUt here is my URL
http://mydomain.com/awarenessroom/facebook_image_share/aHR0cDovL2Rldi5lanVpY3lzb2x1dGlvbnMuY29tL3Jla2xhaW1wYWtpc3Rhbi5jb20vdXBsb2Fkcy9hd2FyZW5lc3Nfcm9vbS9pbWFnZXMvOTEwNzA4ODI3VG9yIERheSBaYW5qZWVyLmpwZw==
and it says "The URI you submitted has disallowed characters.", even if I add = in config, still not working. Can anybody let me know what is required exactly by CI in config to get resolved for URI to be working?