I will try to describe it the best I can...
You see when I finish a match on VS mode or finish a stage in STORY mode, this is what appears...
I can't unlock any characters or level up any of them and I have to quit the game and start it every time when match ends. Please help meh
Ok there are several kind of reasons why this could happen.
1. The first one is described on that error note. Read it.
2. You did not download the new serverfix application that Marti released a few days ago. It is written in green on the start page after your login.
3. You have level 0 characters, but that's most unlikely as you did not even unlock any characters.
^ Somehow this doesn't help me -.-
Nothing from your 3 solvations
If you do have fb, then join the HF group (easily accessible through the hp of HF) and ask either Marti himself or state it into the group as it is much more active than this forum here.
1º - Are you logged in your account?
2º - Did you try in the browser version?
Hope it help.
if you have dynamic ip check if it changed, or if something is blocking the site or anything like that
and try to clear the cache
Try to create another account.
It seems as it repaired itself with new versions, though it sometimes still happens, but it's more than ok now.
I don't have to turn off HF all the time