@Reaper-cet That might help some but not all, like myself.
I've opened all ports, disabled/removed firewall/antivirus software. None of this helped the issue, ran ping plotter and caught no internet issues on my end. This is 100% a server issue and Sega needs to address it otherwise, a lot of people are going to stop playing - the fact that the JP server doesn't have this issue but did have the issue back around 2015 but they fixed the problem.
Because this game is lobby based, any errors like 630 are gamebreaking because it not only makes you lose progress, can make you lose items and hard earned rewards too. Most of the time, I get the error at very specific places which makes it far more likely its a server issue, if it was ISP related or on the users end, the D/C would happen more frequently and at more random times....but considering its very specific its got to be a server issue.
My error 630 log;
Trying to join AQ with alliance members = Error 630 upon joining the gateway ship, happens constantly making alliance party play impossible.
Magatsu AIS battle after beating him and the victory screen displays = Immediate error 630 preventing pickup of any rewards.
Daybreak Province Exploration exploration, transitioning from Area 2 to Area 3 = highly likely to cause error 630
Gone with the wind/rain = group triggering a PSE Burst or worse, a Crossburst = almost instant error 630
These times that cause my personal error 630 are all too specific, and don't happen on the JP server. This has to be #1 Server issue, #2 software issue possibly gameguard related or #3 bad or overloaded node during the hops from server to client.
I can Confirm the Disconnects every time there is a victory screen in an urgent quest for the magatsu fights, both of them.