σφάλλω

this verb usually means to overthrow, trip up, etc., so it is transitive. in Soph., Aj., 1136, this meaning does not fit the context, so LS comes up with a different translation: ἐν τοῖς δικασταῖς, κοὐκ ἐμοί, τόδ᾽ ἐσφάλη this mishap took place by means of . . , S.Aj.1136
is this an ad hoc adjustment to make it fit into the context or what?

Aorists in -ην (without -θ-) are typically intransitive, not passive.

like ἔβην? Then the literal translation would be: this befell through the judges, not through me.

Your original question is misguided. ἐσφάλη is aor.pass., not transitive, and it fits the context perfectly well.
What is your problem?

(Edit. I think Hylander is mistaken to suggest it’s not passive.)

ok, thank you, it was overthrown (or another fitting verb) through the judges not through me.

No. τόδ᾽ is an internal accusative with ἐσφάλη (aor.pass.), whose subject is Ajax. Lit. “he was this-tripped,” “he this-fell,” i.e. “he suffered this fall.”

σφάλλω is a semantically rich verb, usually used metaphorically. LSJ is instructive.

i can see it now.