When I try to load my SimBrief flight plan into the A340 (with ATSU > AOC MENU > FLT INIT or with INIT REQUEST on the INIT A page), I always get an error saying : "INVALID F-PLN UPLINK".

I checked several times and my Simbrief ID is correct.

Does anyone know how to solve this issue ?

UPDATE : Just had to restart the sim..

I've also had this issue today. This is the first time I have loaded the A340-600 with the current nav database. The navdata had apparently updated to the latest AIRAC as expected, but the only way I can get the flight plan to upload is if I select "IGNORE AIRAC/AC TYPE MISMATCH".

Looking more closely at the MCDU I noticed the end date for the AIRAC was incorrect. It shows 16MAY-13MAY, not 16MAY-13JUN, and the database number is one cycle out too (2604 not 2605). See screenshot. Could this be why the flightplan is not accepted?

Edit: l now realise the reason, the EFB never asked for my Navigraph login and as I don't have the charts service I forgot that would be needed. I was thrown off the track by the nonsensical cycle number the system created.

Problem solved and lesson learned.