Any latest developments from this post? I'm also having this problem. I am a member of 3 guilds (was 5 before leaving one to start my own then leaving a second to see if that helped, but with no luck)
Check to see if someone made you guild leader in one of the other guilds you're in maybe?
I was able to make a guild. I am a pc tranafer and could not create a guild on a character that transferred from the pc becauae I was in 5 guilds on the pc, but only 2 on ps4. Tech support says this can't be a ptoblem so I proved them wrong, I started a fresh character on the ps4 leveled to 10 and created a guild with no problems.
Something very wrong happened with the coding with the transfer system because this is not the only problem I have on my pc teansfer characters.
Hope this helps.