You can use the command console to find your IP address. If you are unsure of which IP address to look up, check the bounced mail message and headers for a line that looks similar to this:
550 Service unavailable; Client host [127.0.0.2] blocked using Trend Micro RBL+.
Please see https://servicecentral.trendmicro.com/en-us/ers/ip-lookup/?ip=127.0.0.2
The IP address you would want to check, in this case, is 127.0.0.2.