I also opened thread in SMF forum but did not get reply jet regarding this issue so I will try here, it look like maybe this issue is related with server side and not with SMF as well.
I had SMF forum from 2005, as many of you know is probably best forum in the world, and is usually problem free. Today I noticed one strange issue, I was trying to move one thread to another board - move option - and was not ablle to do that, I get note : The board you specified doesn't exist I try few times and every time I get this note and can not move topics to another forum. Just days ago and in the past I move topics without problem. Nothing is changed in forum for months, no upgrade, no mods, nothing and suddenly one simple thing like moving topic dont work.
Maybe is that related with server side, somebody changes something in my server?

Second issue  that I realize is that many new member (registered recently) after I aprove their membership never login to my site, that was suspicious to me and I register with test acount to my forum, registration was sucesfull and imideatly in my mail I get notification and note that admin must first aprove my registration and that I will get second e mail with autorization. In SMF forum I aproved registration but in my testing e mail acount I never get authorization mail so new member can not log to my forum.
That are very weird because registration mail come imideatly but second aprowed mail never come.
Of course that was working before ( I have 400 + members) and I always have those type of registration with admin aproval , dont know why this sudenly dont work 

Any help?