outgoing emails are blocked by abuseat.org.

I have been trying to send the emails from my account to a gmail one but it is showing error saying service inavailable. Client blocked using cbl.abuseat.org. it was working fine earlier. Any clues what is happening?

Your IP address has been reported 4 times in last 28 days.
https://www.abuseat.org/lookup.cgi?ip=42.108.33.244

I wonder why? I deleted it now it is working. But why would someone report my IP? Maybe cause I am behind cgnat from my ISP?

Very possible. Maybe your ISP is used to spam a lot?