cannot add user to domain, AD DS not found

This is strange.  I've added 12 PCs to my domain (office.local).  There is one PC that cannot contact either of my 2 DCs:

Error "gist": 2 Domain controllers found (with correct names listed), but cannot be contacted.  Check DNS, etc, etc

Checklist:

• This PC has the DNS pointing to the DNS server (192.168.1.29)
• This PC can ping the DC by IP and by name
• No errors on the DC server management dashboard

Any ideas?  Firewall is turned off on the client PC.