Cannot login on server after playing on it once.

What I expected to happen was...:
I would login normaly

What actually happened was...:
I get errors and auto-disconnect

Steps to Reproduce:
1. Play on a external server with auth plugin(simpleauth,authpro).
2. Login always fails and give me errors even when I type in the right password.
3. Tada! You are now disconnected and produced MCPE - 5586.