I joined the game as a spectator. It seems as if "lexicam must confirm line choice". Please
ask your opponent, if they forgot to confirm.
If you still think, this is a bug, please report it at
https://boardgamearena.com/bug?id=0&table=720313420
If you can't continue the game, use the hamburger menu at the upper right corner to either
Concede the game or
Propose to concede the game collectively
EDIT: By the way, it seems as if the game continued. Just some seconds after I answered your question, the game now says that "Fyhs99 must choose tiles". So, it looks like it got fixed.