Fleck the client area, it will give you the reason, if the account area says you are not suspended, (Please note the yellow banner) it’s probably due to this:
I would guess the account is suspended. If some of the files you uploaded got flagged by our abuse scanners, that would trigger a suspension.
If that happens, you need to submit a ticket from the client area to do anything. The people there can tell you why your account is flagged and what you can do next.