Most of the generalized aliasing domains get blacklsited. If you are going to do aliasing set it against your custom domains. From what I can tell: Atlasian an

Most of the generalized aliasing domains get blacklsited. If you are going to do aliasing set it against your custom domains. From what I can tell: Atlasian and Stackoverflow try to reject you based on your mx records on the domain (which makes that a problem) There are a few other companies that try to restrict you to gmail or hotmail domains. (Which is even more frustrating)