Форумы / Cotonti / Extensions / [Plugin] Cotonti Social

Remove & from the call to cot_url and add true as the 4th param for cot_url. The 3rd is an empty string. So it becomes:

cot_redirect(cot_url('users', 'm=details&id=' . $friendid, '', true));

By setting the last param to true, you indicate to cot_url that it shouldn't do htmlentities (convert & to &). This is a requirement when you use it in combination with cot_redirect, because http redirect urls shouldn't be html encoded.

For the record, the 3rd param can be used to set the url hash (#abc).