Constant 90k for me and GF all day

Hi all, me and my girlfriend play FFXIV on our PCs, on the same router, and we're getting constant 90k errors that boot us off at all hours of the day. Our ISP is Mediacom under their 1GB plan and everything else on our internet runs great and speedy except for this one, major problem in FFXIV. To be specific, the speed XIV runs is great but the amount of disconnects and random drops just put a damper on everything. We both enjoy raiding as tanks and healers, and us dropping wipes entire runs to the point of being unplayable.

We've been playing for many years but this only started 2 months ago. We've had various ISP issues that technicians have come to fix, and now everything works except this major issue.

Can a mod or someone help? I've seen thread similar to this one where I can post some computer info or something, and that helps diagnose the issue. Anything will help! Thank you!