I am a member of many websites. I have a problem, because some of these sites automatically generates e-mails and those sent to the address of hotmail.com does not come. I have been in contact with one of these sites, and they confirmed that the e-mails sent to hotmail are rejected by hotmail.com. They also said that the service (hotmail) should add their IP addresses to the whitelist.

Please tell me how to do it?