My emails are back with information "Client Host [79.137.123.220] blocked using Trend M

Hi i have problem from few days. My emails are back with information "Client Host [79.137.123.220] blocked using Trend MicroRBL+." I changed password. I had Eset Security but I changed for Trend Micro Maxiumum Security. I checked ADWCleaner and everytinhg was clean. I talked with my friend about that and he checked our site. I thought, meybe something sending spam from site. No. Could somebody write to me what I can do more ?? I have problem only with one domain, second working normally. My friend suggest, meybe change number IP. Is it will solve our problem ??

Best regards