Error: Protocol Security Negotiation Failure

i have an issue about creating a local user in my sophos and create a  remote client access and RDP connection for a device in my local network ( not on a domain) work group device

i make a local user in sophos firewall

when i make a a bookmark and clientless access and after accessing user portal

it gave me an error

Error: Protocol Security Negotiation Failure

although i recheck my pc several times