Board Game Arena

We are playing on this table: https://boardgamearena.com/1/orapamine?table=801615361

And the board is pretty clear but we both send answer already and the game say it is invalid...
So both of us just ask for additional hint which just confirm our answers...
And of course, none of us want to lost the game asking an incorrect answer.

https://ibb.co/cSXqJgQC

Should we open a bug ? or we are dumb and we dont see what is not correct

I can see another possible answer, this is tricky one

ahaha yes my opponent find it.

This clear triangle is so tricky !!!