What does this Protocol Error Mean?

We recently updated our website and in doing so broke access for some of our Macs. They run MacOS 10.12.6 We're seeing errors such as these:

3/17/22, 8:01:32 AM failure when provising url

'https://lib.skidmore.edu/#library-catalog' error 'Error

Domain=NSPOSIXErrorDomain Code=100 "Protocol error"

UserInfo={NSErrorFailingURLStringKey=https://lib.skidmore.edu/#library-catalog,

NSErrorFailingURLKey=https://lib.skidmore.edu/#library-catalog,

_kCFStreamErrorCodeKey=100, _kCFStreamErrorDomainKey=1}'

3/17/22, 8:06:32 AM failure when provising url

'https://lib.skidmore.edu/#library-catalog' error 'Error

Domain=NSPOSIXErrorDomain Code=100 "Protocol error"

UserInfo={NSErrorFailingURLStringKey=https://lib.skidmore.edu/#library-catalog,

NSErrorFailingURLKey=https://lib.skidmore.edu/#library-catalog,

_kCFStreamErrorCodeKey=100, _kCFStreamErrorDomainKey=1}'

Can anyone tell me what they mean? We've made no changes to the clients, but without understanding the errors, it's hard to troubleshoot what is going wrong on the server.