Not able to mark posts for 'solution'

I have a few ‘solutions’ recently (not aiming to boast) but none of the requesters seem to be able to mark this as ‘solution’ … why? And if selective…why ?

Probably because the topic was not given a forum category when it was posted. Solutions can only be added to posts in categorised topics.

Could you check this one then? Seems of Cat ‘energy’ but op cannot mark he says
Transfer old m³ to new kWh sensor - Energy - Home Assistant Community (home-assistant.io)

EDIT: I just marked this ‘Social’ but cannot tag your post for Solution too …