Cannot update maps by the latest GarminExpress 7.17.3.0

You mention changing to another computer, was it also running GE 7.17.3.0?  Were both computers running the same OS?  Were both computers laptops or were they desktops? 

Yes, both are windows 10 laptops, same version of GE. I do not have other systems.

Some things to try...

With the GPS disconnected do the following:

Open GE, click on the settings icon near the top right corner, if needed select "General", then disable "Always keep Garmin Express running in the background".  Exit Garmin Express.

Go to Task Manager (select Run as Administrator if possible), then select the "Startup" tab, scroll down to Garmin Express, right click and then select "Disable".

Disable USB Selective Suspend. This is a feature that turns off the various USB ports on laptops in an effort to improve battery life. Instructions on how to disable it can be found at How to disable selective suspend.

Reboot the computer.

Have the computer operate on power, not battery.

Start GE, then connect the device and retest..

Thanks for the tip, but no go as well. Exactly same thing happened. 

One more thing to try would be to find the executable for Garmin Express...it should be located at C:\Program Files (x86)\Garmin\Express.  Then right click the executable express.exe, chose Properties, then select the compatibility tab.  Run the Compatibility Troubleshooter.  In my case, and the circumstances aren't exactly like yours, Windows 10 (a few years ago) the troubleshooter selected to run the file with a Windows 8 compatibility.  All my issues went away and to be honest, I'm afraid to set it to Windows 10.

If that doesn't work, and lots of people had issues when 7.13.3.0 came out, they found resolution by rolling back to the previous version 7.17.2.0. 

where can I get older versions of GE? 

I can't vouch for this but supposedly older versions are available at Older versions of GE.  If I was to do this personally, I'd download the file, assuming that is what you do, then independently run AV against the file.  As I said earlier, when 7.13.3.0 came out numerous people stated that rolling back to 7.12.2.0 got them a working version. 

I had the EXACT same problem on my Nuvi 40. I went through various fault finding steps, of which nothing worked. What eventually worked for me was to first close Express if it's still open or running in the background, then find the Garmin Express executable file, right click on it and then ran it as Administrator. I am the only user of this computer and I have administrator privileges set up up, but when staring Garmin Express that way sorted out my problem.

Unfortunately that website never worked for me, it always give me 404

The “older” versions link I provided earlier works fine for me from an iPad.  But do a Google search using “uptodown Garmin Express” (without the quote marks.  It should be the first hit.