Cannot access new Windows 10 computers remotely

Check to see if the  firewall is on, if so configure rules to allow ping and remote control ports.

ok. but hard to do since I am trying to connect remotely.   I only go there once a week

How do you connect to these computers  by VPN? if so might your site and the remote site be using the same subnet such as both using 192.168.1.x ?

I use Citrix.   I can see every computer except for the 5 new computers

I was able to have one of the users turn off the firewall on the computer. Rebooted it still can't see it

ping and remote desktop access is blocked by default
as an administrator can you access the machines administrative shares i.e. C$ ? \\computername\c$ ?

If no ping..no connection then something is blocking you...(wrong IPs ? problem DHCP)
Since you have/can have someone at site i guess your best best is to guide the man/woman to install TeamViewer and work your way from there....

Team Viewer is a good idea.

Are there existing PCs or servers at the problematic site to which you can connect in the same way?

Yes 22 of them.   It is only the "new" Win 10 computers we added last week.   Note we have many other Win 10 computers?

Almost certainly has to do with security software, firewall or add-on antivirus. As David said ping, RDP, and Citrix connector would be blocked by default.  Are you sure it was disabled or do you have other 3rd party security software such as A/V.  Or, could it have anything to do with Citrix licensing limits?

Definitely not Citrix licenses.  We use Sophos AV.   I will check it but do not think that is the issue.  

We add computers all the time and have not had this happen.  

My assistant will be there today to start troubleshooting.

Googling there are others with various issues using Sophos and Citrix.  Might be a good place to start the investigation.

Can you connect to another workstation and from there to a problematic PC.

On another note. I have seen all sorts of network related problems with Win 10 1903 update.  Might the new ones have it and the old do not yet?

well, my assistant informed me he never turned on Network sharing.  I did not think of that because he always does.

Which would have set the firewall to block incoming traffic I assume.
Thanks for updating.