Can't send patch or mail to mail01.ipfire.org:587 - authentication fails

Hi,

I just tried to send a small patch with "git send-email...", but GIT keeps telling me:

***SNIP*** Password for 'smtp://mfischer@mail01.ipfire.org:587': 5.7.8 Error: authentication failed: ***SNAP***

I didn't change anything on my side - GIT-version is 2.15.0.

Bug or feature or anyone else experiencing this? Any hints?

Pushing with "git push mfischer..." was OK.

Best, Matthias

P.S.: Sending this mail with my IPFire-account gave me: "Login to server mail01.ipfire.org failed".

P.P.S.: Second try - with IPFire account...