Why I cannot send private messages?

Hello! I just realized I cannot send private messages to other members of the forum. The messages stayed in the out box instead of the sent box. Is it just me or this function is disabled for the whole forum?

I have checked the technical settings of this forum: it should be possible

If messages "wait" in the outbox this is likely more a temporary issue (maybe sending is done by a scheduled job which only runs from time to time).

@other users: Please tell me if you have problems with PM, too.