This only happens with wind phones that I do not receive their phone calls but I can call them.. I've tried calling koodo and they said that their was no issue on their end. Ive checked my settings, my friend is definitely not blocked.
I went and gathered some info to help. In most of these cases, it's because the contact was blocked on the receiving end (which would mean you blocked them). Please double check in your Settings -> Phone -> Blocked and make sure that their numbers are not there. If they are, unblock them and restart your phone. When it comes to issues with calling between two parties, in most cases it's the outgoing end that has an issue with the service since it's not routing the call properly. I suggest having your friend contact WIND to let them know about the issue so that they can troubleshoot further. Hope this info helps!