Forgive unsuccessful service β then turn on computers etc (3,2,2)
I believe the answer is:
let it go
'forgive' is the definition.
I know nothing about this answer so I can't tell whether it can be defined by this definition.
'unsuccessful service then turn on computers etc' is the wordplay.
'unsuccessful service' becomes 'let' (tennis).
'then' is a charade indicator (letters next to each other).
'turn' becomes 'go' (a person's move in a board game).
'on' says to put letters next to each other.
'computers etc' becomes 'IT' (short for Information Technology).
'go' after 'it' is 'itgo'.
'let'+'itgo' is 'LET IT GO'.
Can you help me to learn more?
(Other definitions for let it go that I've seen before include "Excuse something" , "Hit song from Disney's 2013 animated feature film Frozen" , "Refrain from comment" , "Disney tune" .)