It doesn't appear to be possible to enter Myr Embassy on Mhen'ga, despite the map graphics indicating the path to it is open. Not sure if this a bug -- as i have visited the place a few weeks earlier in the game and maybe it closes afterwards? But if the intention is for it to be only accessible once, then the map could use one of these "no entry" icons once you leave it, as it's currently confusing.
Attached: a savefile with no access to the embassy.
Attached: a savefile with no access to the embassy.