So, I'm guessing from what you posted, you have both of these AirTags currently with you now ... correct?
Are they over a year old? If either, did you change their batteries?
As far as location, AirTags rely on Bluetooth. When they are near your iPhone, this is what is used to communicate their location to the phone. When they are outside of 30-50 feet of your phone, they would rely on other iPhones that are near them to receive that signal so that it can be sent to the Apple servers. In turn, then you would get this location via the Find My app.
If neither have been providing location updates (which appear to be sometime now), then either of the following would be true:
- Neither were able to send their respective Bluetooth signal, or
- There were never any iPhones nearby (not likely I would think.)
Just to be sure that you reset your AirTag properly, please take a look at the following support article just to rule out if you missed any step along the way: How to reset your AirTag - Apple Support
If that doesn't resolve the issue, and you know that the batteries are still good, your next step would be to contact Apple Support directly for further assistance with this matter. To do so, simply select the "Support" link on the lower left-hand side of this forum's web page.