We are also having the license activation problem. System log of the server is also reporting a Schannel Error. Seems to me there’s a cipher negotiation issue. Ours is a Windows 2012 system, but we’ve used IISCrypto to clear out dead/bad ciphers, and disable 3DES, but there are plenty of other ciphers to use. Just ran a check via https://www.ssllabs.com/ssltest/analyze.html?d=theucguys.com, looks like you’ve killed supportability for IE11 unless running on Windows 10/Server 2016.
