Access -> resume games -> never loads

Using OGS is not something i do much frequently, but in all the last times i remember, i received notifications for a resumed game. I never clicked to see it, assuming that it would appear in front of me whenever i played something. But i played some games, and nothing happened but them. They finished, and then i was - again - free to browse around here.

Ok. So, there is a number of notifications in the upper right area, above my photo. By clicking there, i see the “restarted game” notifications. But when i click on one of them, something strange happens: an empty board appears with the warning “Loading…” over it, but this never ends. Minutes and minutes waiting… nothing. And the address bar, at this moment, for that window, has “https://online-go.com/game/undefined” in it.

So, what is wrong with the games i played, or with the games in my account? (or something else?)