connect to mx0.gmx.de[213.165.64.100]: server refused to talk to me: 554-{mx013} Your address is listed as dynamic on SORBS (dul.dnsbl.sorbs.net) 554 We are currently not accepting connections from such hosts. (port 25)

what can i do?

from begining on it worked fine, but suddenly not, additional to this i must say, that im not in contact with my isp, because, actually they canceled my contract, but they forgot to unplug me :-)
so if i need help from my isp this is not possible, but im really not a spammer, i sent about 60 mails the last 6 months, how to unlist me from there?

Good luck in getting de-listed. Especially since you are not able to contact your ISP. Why? If you are not able to change the DNS PTR record for the IP address of your mail server (which will require your ISP's help), then SORBS is NOT going to de-list you.

see: http://www.us.sorbs.net/faq/dul.shtml

i got it, but one question, i followed the instructions on the website of sorbs, and requested that, but the question is, will they contact my isp without letting me know? yes or not?, because if yes, then i will have a pain in my ass