I am unable to continue the main quest line for the Martyr chapter 4.

My game disconnected during the Van Wynter Legacy mission: Explore the coordinates Grexus provided, while playing in multiplayer. I reloaded the game and completed the mission but it did not complete in the journal so I am now stuck at that mission and unable to continue. I am playing on PS4 and my profile name is Holythunder1 and my character is Sebastien.

If anyone knows a way to bypass this issue it would be appreciated.

Thanks.