why some members haven't Group tab? I invited my friend [user:http://mirror.codeforces.com/profile/araz] to group , when he click on invitation link, GROUPS page showed but table of his groups are empty and nothing happened!
This happened before for my other friend. What he can do ?
This happened with me once . So I logged into my account through my friend's computer and then I could successfully accept the group invitation .
Same problem here :/ And I can't join even from my friends' computers
I couldn't find any reason or solution !
finally deleted him from group and invited again, then it works. ( but for someone even this and accepting from other computer did not work! )