Images are always helpful, video even better, but generally more effort and harder for most players to sort out. Either will give important context, often showing things that have been taken for granted - expected to be uninvolved with the issue.
Anyway, yeah: anchoring can be a real fiddly nuisance, sometimes seemingly impossible. But check out the following (on a flat area where anchoring looks possible):
Grab you tech in build build, first, before clicking anchor. It just tends to work far better. It holds the tech level and at a good height off the ground, preventing the jerking up motion (that can drop resources, etc).
Make sure that, underneath your tech, there aren't any bases of mined out rocks or crystals. They can block anchoring when they shouldn't.
Wheels can dangle down quite a long way on their suspension travel (without weight compressing them). Make sure you're allowing for this, that the wheels should be fully off the ground when anchored.
Make sure, also that there are no extendable or moving parts, like solar panels, or turreted guns, that invisibly take up spaces that might be intersecting the ground, when trying to anchor.
