Google Apps Alias limitations

Like many others I use Google Apps account for my emails and I have more than one domain that I add as Alias to Google Apps primary account. For quite a while I’ve been wondering if there was a limit of how many aliases I can add to Google Apps and I wasn’t able to find it anywhere in Google Help or other blogs via google search. So today I finally found this out by reaching the limit of Aliases in Google Apps (the paid Gmail).

The number of aliases you can add to your primary domain is 19. so the 20th is your primary domain.