linux + firefox. not sure what happened to me yesterday but the challange/response thing was borked and when i finally got through it all, it said i was a robot anyway. this was while trying to sign up for a skype acct, could have been a ms issue though and not necessarily cloudflare. i think the solution is to just not use obstructive software. thanks to this issue i discovered jitsi and that seems more than enough for my purposes.