I had something similar this morning with my Guardian ... I couldn't log in (he was on his starship) but I could log into my alts w/o a problem.
About 30 minutes or so later, I was able to log into my Guardian; however, I could not access my Legacy Cargo hold or transport to my Strongholds while on the ship. After leaving the ship, I was able to enter my strongholds & access the Legacy Cargo Hold for my Stronghold.