What’s the best way to fix this fence line erosion?

How much higher is your lot than the empty lot next door? Does your yard stay level up to the fence, then taper down to native soil?

Haven’t measured but with eyeball test pretty even.

Oh I know. Not happy with company that put fence up. It was a while back and have had problems with it since a year after they put it up. It’s a reputable company in the Jackson area, but have talked with many people who are not happy with their work.

Somewhat. Brush cut as well.

only way to stop that is to fill in with dirt from other side of fence and tamp down well, then spread rye grass seed over it, its cheap and grows fast to establish a root base to hold the dirt in place and then real grass will quickly take over and smother it out.

if i had to guess i would say you had armadillos or something that were digging under the fence to get in your yard.

once you build up land at least a foot on the other side of fence your yard will stop washing out like that.

Lots of places I keep sprayed erode easily. No turf/roots to hold the dirt. That was my guess.

Scrolling all the way to the left, I see something that isnt erosion, it's more of a sink hole type problem. And that center section of fence has been removed and put back..you can tell by the runners. You said a reputable company installed the fence, which tells me that no matter how shitty they are, NO WAY they didnt have the runners lined up.
I'm sure you have your reasons, but the whole story isnt being told here. Ground that is basically level, doesnt have erosion and sink holes

Pea Gravel works really well also. I have used that to stop various spots of erosion in my yard.