500 Error when trying to install theme

[Firepup650 (Firepup Sixfifty)]

Ah, this seems similar to an issue I already reported then:

@Firepup650

Message

Failed to process hijacked response correctly : ActiveRecord::RecordNotUnique : PG::UniqueViolation: ERROR:  duplicate key value violates unique constraint "index_child_themes_on_parent_theme_id_and_child_theme_id"
DETAIL:  Key (parent_theme_id, child_theme_id)=(50, 35) already exists.

Although in your case it looks like the theme ID it’s trying to use (50) is already in-use, instead of the parent-child link like mine was.

Did you add a theme earlier that failed for any reason before the 500s started?