Firstly run Malware Bytes full scan https://www.malwarebytes.org/ and remove all viruses and adware which you will have due to the lack of anti-virus.
Then retry the server.
If you still have a problem, ask the server owner to update to the latest stable version of MTA 1.4 here: http://linux.multitheftauto.com/
After they have updated, you can then select this option in MTA:
Settings->Advanced->Packet tag->On