Here are some answers to your questions:
Does this happen in a new user account as well? Test it out to isolate this issue:
Only one user account on my MacBook Pro
Does this remote connect using Bluetooth? If so, unpair it from your Mac, restart, and pair them back together again:.
Uses either. Have tried only the alternative to Bluetooth, since the remote doesn’t show up when trying to connect with Bluetooth.
Also, check the battery of your remote to make sure it’s completely charged and test with another Mac if possible.
Have installed a brand new battery, and have tried the remote on both my MacBook Pro, and my iMac.
Should mention that two different remotes are not working, though it will work once, then quits. The older remote used to work just fine, but quit working properly after a system update about several weeks ago. AND, just recently discovered that the remotes seem to work OK usually—when using Keynote, but no longer with either PowerPoint or Google Slide. This makes me wonder if there’s an incompatibility problem with the newest MacOS updates and other brands of presentation software. The iMac is running Catalina, the MacBook Pro is running the latest version of Mohave..
Thank you for your assistance.
—Terry Roberts