Scoring question

[archer]

2 outs and a runner on third. Pitcher throws a strike 3 looking pitch, the catcher cannot hold onto the ball and the runner scores from 3rd. Runner advances to 1st.

How is that scored as an earned or unearned run?

According to the explanation I got the dropped strike 3 should have been the end of the inning and an error charged to E2. It cannot be considered a wild pitch or passed ball due to the pitch being a strike 3 looking. The run should be considered unearned as well as any run after that because the inning should have been over.

What are your thoughts on this?

Thanks