Hello Matthias,

assuming you tried to log in from an IP address assigned to DTAG and 
used for dial-up-purposes (80.144.x.x), there have been indeed four 
failed SSH login attempts from it on Sunday morning (~ 08:00 CET).

The same IP address caused one failed SSH login attempt again yesterday, 
at 15:56:44 CET, but did not exceed the limit this time. :-)

Sorry for the inconvenience.

Thanks, and best regards,
Peter Müller