well, are you 100% sure you have the ladder put together the right way< and are using the tree arm right(correct spot on ladder and to tree?)
and last is the ladder sinking in the ground at the base of the tree where legs of ladder meet the ground, or is it slipping at the TOP of the tree where the stand meets the tree?
the reason I ask, is, a ladder will BOW a little when there is weight at the top, and pending where and how you place the AR that attaches from tree to ladder, can determine how much BOW you get or not
some times you have to stand on something to get this arm high enough to NOT make the ladder bow a lot when your up top
closer to MID way point on ladders seem the best to me and you want this arm to be SNUG to tree and NOT be pulling ladder in OR out off angle, you want it all straight ,holding solid!
next, if the top of the ladder itself, it need to be level and strapped to tree TIGHT and normally in TWO spots on Buddy like stands
I normally ditch the cheesy straps they give and add straps that are much HIGHER load holding rated and higher breaking points
YOU can still use the one's that come, but I always add extra's for peace of mind
yrs back to prevent things from getting stolen, I used to take metal straps and BOLT the top sections of the ladder stand to tree using them and some HD lag bolts(Only where legal or have permission to do so, of course )

But this also makes the stand a little safer too as it would have to BREAK the steel I used to pull off the tree or up/down on ladder too
BUT you don;'t want this to be the MAIN deal
stand s need to settle in
and as tree's grow, things need to be re adjusted, there not a set up once and be done, HOW fast a tree grows can mean a lot on how often you have to re adjust or replace straps, they do get damaged from stress of a tree growing as well as being exposed to UV /sun light and weather, plus have seen some critters chew on them. SO< every so often , you have to inspect them and re adjust them!

but getting the stand level with YOU IN it, and then snugging up the straps might be what you need to do
I am able to use a ATV on lands I hunt and as such I BRING a Ladder with me, I find this the safest way for me to hang stands, plus I SEE what things look like fro above , before working and placing a stand UP to find ITS Not the best place for it!
being able to use a ladder makes life easier, and safer, and I can also carry a few ladder stands at once with me, saws and any tools needed too!

here is a pic of my atv with a ladder stand(15 ft) and a 15 ft ladder under stand, I have carried 20 ft stands and 24 ft ladders often over the yrs, like driving a BIG rig thru the woods at times, but most times I can get right to the tree I wish to use, and can even use my winch and a snatch block to raise the ladder stand up the tree, again due to having the ladder with me,, makes hanging/setting up big heavy stands alone pretty easy and safe!

​​​​​​​