Hey all! We're aware of an issue getting into champ select and are looking into it.
~~Update: You should be able to get through ready check now and into game. We're going to keep looking at this and may do some additional PBE work later. ~~
If you're still encountering this issue, please relog and try again. If you're still encountering this issue after relogging, please make a ZIP of your Logs folder in Riot Games > PBE > Logs, upload them to a file sharing service, and link them here.