I just had a player accidentally unsubscribe from an event, and I checked this on my end, turns out when you unsubscribe from an event you can't resubscribe. When you attempt to resubscribe the buttons to do so is missing in OTM. Instead on the other side of the screen there is just a little tickbox confirming you have unsubscribed. Seems kind of pointless for that limitation to be in effect, suggest changing it so players can resubscribe themselves to events.