No login possible

It’s suddenly not possible to login. WP says the password is wrong. I looked for the password hash with phpMyAdmin. it’s not that I can generate with MD5 tools. I asked for email to enter a new password. Entered it. WP accepted. But won’t me login afterwards. Same error message. Sometimes also:

Service Temporarily Unavailable
The server is temporarily unable to service your request due to maintenance downtime or capacity problems. Please try again later.

When I add the MD5 hash tag of my password by phpMyAdmin in the DB field directly it will be completely changed after a while.

That’s the situation for 2 months now.