In December 2014, Muscat had a private meeting with the Prime Minister of Azerbaijan

This is an article published in the Azerbaijan press in December 2014. The original is in Azerbaijani, and I have linked to the translated version.

It says:

The Cabinet of Ministers told Trend that the Azerbaijani and Maltese Prime Ministers met in private. Then the meeting continued in an expanded format with the participation of delegations.

Azerbaijani Prime Minister Artur Rasizade noted that many important issues were discussed at the meeting in private.

This is the first published evidence we have that Joseph Muscat met the Prime Minister of Azerbaijan, Artur Rasizade, completely privately – and it had to come from the Baku press.