Terminal Failing to login
This has happened to me in the past and just happened again on a Mac running High Sierra (10.13.5) that is bound to an Active Directory domain.

Turns out it was caused by an active Cisco IPSec VPN connection. The VPN connection likely hijacked my DNS settings and broke local name resolution that relied on using the AD server's DNS.

It also broke access to the Users &amp; Groups System Preference panel.

Try disconnecting your VPN and reopening Terminal.