When I try to link my account through PS4 menu it says "Now processing" and nothing happens. Even after several attempts game still says "Now processing". That's all. Anyone has this issue too? 

Restarting the whole console helped me. So this isn't a deal anymore. Sorry for bothering. 

Your tip just saved me from sending in a ticket. The whole console restart worked.

Didn't help for me. 

Same. We are 3 ppl living in different towns and cannot connect em. Every time we get a network error, besides the fact that we have a perfectly fine connection. 

Mine will not connect either tried that twice.

I was having this issue but console restart solved it. Initial cause was a firewall ad block on our router, it was turned off but the PS4 never realized it.  For anyone still having linking issues(error:400) maybe take a look at what your router might be blocking.

I had the problem too. I just closed the game and after logging in again it worked. 

I had the error 400 as well.  I fixed my issue by setting up port forwarding.  Fixed profile authentication errors as well. 

Still does not work at all, I have an account but I still says it doesn’t exist. How the heck can I get all my pre order stuff and be in game and have no account....can’t claim sky hawk......