"They didn't go on a honeymoon."

Translation: Elles ne sont pas parties en lune de miel.

[Marian294044]

I used "ils ne sont pas allés" - can't see why it was rejected

[Sitesurf]

"Partir pour sa lune de miel" or "partir en voyage de noces" are set phrases.

"Aller en" is not wrong but less natural.

[James-Cici-HY]

Now, "Ils ne sont pas allés en lune de miel" is accepted.

[JuneDowns]

I don't understand why 'Ils ne se sont pas partis ... ' was rejected.

[Sitesurf]

"Partir" is not reflexive: Ils ne sont pas partis...

[Brian826478]

Are we supposed to infer the sentence "They didn't leave on honeymoon"?