If a tracking error appears just after clicking the analyze button, make sure you don’t have any extra effects on your footage, like.
Noise reduction
AI Super Scale
Lens Correction
Speed ramps
Other similar effects that may affect the video you're using in such way
Try to turn those off and track again. Some effects applied on the Color Page also impact Fusion, so disable your grading before you track.
You can try to use Adjustment Clip as a source for the tracker node for it to use background without any extra effects.
If you want to use Tracker, make sure you have full viewport resolution (Playback → Timeline Playback Resolution)
It's good to use Compound Clip to have a specific fragment to track (tracker works on full video duration, so if you would like to track a fragment of your video, prepare a fragment of it so it doesn't track the full length of your footage).
Make sure that if you enter fusion your composition starts with frame 0. Select Legacy Fusion Composition Frame Count in Project Settings → Fusion (option available from DaVinci Resolve 20 version).
The longer, higher resolution video the tracking process will take longer and will cause more strain on your machine. Remember, you can track different channels of your video or increase contrast/sharpness on source footage, just to get more accurate input for tracking data. You can always adjust/remove track frames from the path if you have jumps/glitches on your result.
