We recently had an issue where when trying to join machines to the domain we encountered the following error.
“The following error occurred attempting to join the domain gwlab.net”
“No more connections can be made to this remote computer at this time because there are already as many connections as the computer can accept”

If you read through the walls of web pages you will find it’s often due to the number of licenses available on the server. This was not our case at all.

The issue was somewhat more simple.
The systems we were attempting to join all had the wrong time. In our case they were off by about 15 or 20 minutes and had come from our supplier this way.
Not the greatest error description for sure!

Simple fix. Change the time on the local system to be more close with the Domain Controller(s) and then attempt to join.

One additional thing I found very handy was the ability to join the domain using a specific server. The best way I found to do this in our situation was with powershell. All systems were Windows 7.

Open powershell
Type add-computer -?

Specifically: “add-computer -DomainName gwlab.net -Credentials washburng -Server gwlab.net\DC2″

Tons of other options I recommend considering but this for sure makes pointing to a specific DC a breeze.