Normal Map Baking Issue

When baked in Substance Painter, such gross errors appear on the normal map. How can this be fixed?

Don’t know the real geometry or you substance settings (nor substance) but seems to be too small island borders if this would be done in blender.

This is a game model from a game whose UV map I cannot change. I tried and Smooth in different ways, but the artifacts still remain.

What ?? You didn’t baked this yourself… then your title is misssleading.
You have a normal map which doesn’t seem to fit the UV’s ?? Then is was a problem while extracting from the game… whatever. Try to scale the UVs a little (0.99/8 ) while the pivot point is set to original origins…

no, I baked it myself) I just said that I took the model from the game, and that you cannot change the UV.

With UV itself, everything is fine, only one of me has such an artifact.

The island border doesn’t change the UV’s in blender it bakes beyonf the border of the UV’s so some artefacts on the border are avoided. I guess there is a similar parameter in substance… so you baking settings aren’t optimal. But this is a blender community…