@StanL 

Start with the basics...

Be sure the SSID is not hidden.

Be sure you are using the power adapter that came with the router.

Some routers and devices do not like some special characters in the name/password.

Try different devices to see if you can see the network as it may be the device.

Can you enter the SSID and password in the device manually and make connection?

Power cycle the router and the device.

If you used the same SSID as the old router, delete (forget) the network and reestablish it.

Are the antennas connected correctly?

Do a factory reset and re-enter the settings.

Be sure the firmware is up to date.

Use a network tool to see if the network can be seen.

@ArcherC8 Router might be bad.  I purchased an AX21 to use RE505X boosters instead and everything worked fine.  I'll call support sometime this week.