I had the same problem today. I switched instances and it worked fine. Still glad I submitted a ticket.

Having the same set of issues with solo mode that some of you are having. No mission shows up on my ship. I'm still able to pick it up from the droid on the fleet, but after I talk to Theron Shan, I keep getting the tactical flashpoint only. The NPC outside of the flashpoint entrance doesn't give me a choice between tactical or solo. Resetting or abandoning the relevant missions doesn't seem to change anything. My game is acting like solo mode doesn't even exist. And as Raylan said above, this is all after the 3.1 update.

We've had PVP on Oricon twice this week already. Just finished a session a few minutes ago.

I had similar problems with Patient Zero, even though I wasn't part of any group before starting the mission. I used a lvl 54 Vanguard tank with Elara Dorne as my companion. My gear wasn't that great (mostly orange with some purple mods) . In order to beat PZ, I had to (1) Activate "Heroic Moment" right before the fight (for some reason I couldn't seem to activate it in the middle of it), (2) Hit him with my legacy attacks right at the very start, and (3) Use an Aim stim in order to increase my damage. His heals are innate, and there doesn't seem to be any way to interrupt them. Interrupting his attacks is probably helpful, though in my experience it wasn't critical. Even with a tank spec, my healer companion, and increased damage output from the stim and my legacy attacks, it was still by far the most difficult fight during the Arcanum mission. The end boss was a piece of cake compared to PZ.