Cannot play with friends due to "You must have a valid roster"

[brandonbrowning]

I get this error whenever I play with a group of friends, but not when I play alone. Here's the things i tried:
- restarted my pc
- tried different hero combinations, confirming no overlap with anyone in the party
- verify integrity of game cache
- uninstalled and reinstalled the game
- tried for multiple days

I'm pretty sure my account is in a buggy state. Any other ideas?