Account issue

[xxytan]

when I tried sign in my account, even I typed the correct password, but it still noticed me the account username or password is invalid

I'm sure I have typen the correct email and password

and when I'm trying resetting the password, it noticed me again that the account doesn't exist

IM SURE I HAVE REGISTERED ACCOUNT BECAUSE I JUST SIGNEG IN THE DASHBOARD FEW DAYS AGO