Probably an obvious thing to most but I sailed to South Vern without completing the guide mission and was greeted with this beautiful prompt:
Apparently you’re not allowed to enter South Vern unless you step into a glowing circle in Vern first.
What is that super stretched text? It looks like the start of some 2000’s DVD text animation 
You need to do the quest chain and through north vern i believe
Yeah, looks like it. I teleported back to Vern and it tells me to go here:
Edit:
Literally just had to step inside a circle to be allowed to go to South Vern somehow 