Unable to join Clash game

From Riot Website: To join or create a Clash team, you need to have:

Reached level 30 Completed placements in at least one Summoner's Rift ranked queue Be at least Honor level 2 Verified your League account by SMS (this is a new Clash-specific feature)

I fulfill all of these requirements, but when I try to join I get the following error:

Error. Unable to accept team invite. Check the service status and try again later if this keeps occurring.

I've been trying all day and still unable to join.

Please help