Looks like too much water. What’s your weather been like this Spring?
Are they in pots or in the ground? Or both? Drainage may be an issue - not much you can do about too much rain, though. Their roots are way too soggy and are suffocating. :(
If these are in the ground, maybe you could dig up each strawberry plant in a “chunk” of soil w/ a few roots showing @ bottom of chunk. Even a large hand spade should work. Chop a little soil away to form a sort of cube, or “plug”, maybe 4” x 4”, x 3” tall. Fill hole with new soil. (Maybe use cheap potting soil?) Set “cube” on top. Water in moderately, once, and thereafter only if it seems to be getting too dry or you get no rain.
This is just a guess based on my digging up some strawberry plants that had invaded an area where I didn’t really want them. I had just “dumped” the dug up plants with their clumps of roots and soil beside my strawberry bed, thinking I might start a 2nd bed a little later, with survivors. Naturally I got distracted by a family matter. By the time I had time to mess with them, the dug up plants did better just sitting there on the ground in their big spadefuls of soil, than the strawberry plants in the bed.
I assume Diana may want to weigh in further, as she has much more experience. Mine might be a fluke...