What is the ruling on worshippers who prefer to pray in the mosque's courtyard and do not enter the prayer hall with the congregation behind the Imam?

The ruling on congregational prayer in the mosque courtyard before the regular Imam is twofold:

Firstly, if they pray a separate congregation before the regular Imam, this is forbidden. However, the stronger opinion is that their prayer is valid, though sinful.

Secondly, if they pray with the congregation in the mosque courtyard: If the courtyard is inside the mosque building, their prayer is valid. But if it is outside the mosque building, and there is an obstruction between them and the Imam that prevents passage, then there is a difference of opinion regarding the validity of their prayer, because the Sunnah is for the rows to be connected and close to each other.