VDI having login issue 10061 socket error

Citrix as connection broker? 

https://support.citrix.com/article/CTX236975/unable-to-connect-to-the-server-contact-your-system-administrator-with-the-following-error-when-launching-desktop

https://support.citrix.com/article/CTX237357/socket-error-10061-and-unknown-client-error-during-session-roaming

Make sure all required firewall ports are open: https://docs.citrix.com/en-us/tech-zone/build/tech-papers/citrix-communication-ports.html

If your using NC2, make sure to adjust the UVM security group

Can you confirm the requried ports are open between end user & citrix environment