They are having a lot of problems with disconnects.
They have not mentioned what servers are having the most issues/trouble but anytime I am in a group with someone that connects to an again server the problem seems to happen more often. This could just be my imagination or maybe not. But it does seem like Asian servers are having the most issues but everyone does experience delta disconnects at some point. Some more often than others.
Players have reported these issues and they say they are looking into the issue/problem but it hasn’t been fixed just yet. I have noticed personally that certain times of day is better or worse. So keep trying and hopefully you will be able to connect and stay connected for a length of time.
But you are not alone in the disconnect/delta issue. Many others are having the same problem. Hopefully they will fix this soon but we never know when “soon” will be.