WIndows CE 5 not connecting on a new server infrastructure 2012 R2 and wich version are supported?

I have many client Windows CE 5.0 connecting to two (2) webfarm

1. the first one is for testing
2. the second one is for production

We have Windows CE clients working well on test build two years ago with windows server 2012

Now we switched in production and the client receive 

BECAUSE OF A SECURITY ERROR THE CLIENT COULD NOT CONNECT TO THE REMOTE COMPUTER VERIFY THAT YOU ARE LOGGED ON TO THE NETWORK; AND THEN TRY CONNECTING AGAIN.

After SOme investigation we found the problem is related on the certificate created by license server to 4096 bit key lenght

There is any workaround to make possible connection from Windows Ce 5.0 to WIndows Server 2012 R2

Which Version of Windows CE /Mobile are supported with remote desktop services with Windows Server 2012 R2?