If you receive a similar bounce message to below:

“571 Email from (IP NUMBER) is currently blocked by Verizon Online’s anti-spam system. The email sender or Email Service Provider may visit http://www.verizon.net/whitelist and request removal of the block. 131007″

You are likely listed in Verizon’s IP blacklist. This is a privet list that Verizon operates, and cannot be queried or searched.