Problems with MaxBulk Mailer

Hey guys,

I use MaxBulk Mailer for mass mails with a VPS smtp server.
The software works 1 week - now it doesn`t connect (other smtps works)

Thunderbird can connect.
On a different wlan ( other provider and ip) MaxBulk Mailer is working with vps.
I changed nothing...
Any ideas?

Update:

Tried it on the computer of my brother - same problem here.
Hmmm - could my provider ban my IP? But this is bullshit, IP changed every 24h and thunderbird still work.

So, no Problem with the computer...