Can't get past connecting more than 21 clients

Hello,

GSS 3.1 MP2

WinPE10

Running on Windows 7 Pro

Everything's working fine unless I tried to image a lab with more than 21 computers. It doesn't make a difference whether I use the Ghost cast server or in the main console, everytime only 21 will connect & the others say bad credentials 1223. I've tried several times & it's never the same computers that error out. The first ones to hit 21 are fine & the rest error out. I do an ipconfig on one of the failed computers & it does have a correct dhcp IP & can ping the console. Doesn't matter if I do a lab of 25 or 31, still get only 21.

Any ideas please?