Same issue here for about a month now as well on Tonberry. Some days there's no problem at all. Other days I login and get one of these errors 5 times in less than 30 minutes. Some days it's bad enough that anything instanced is unplayable.
All while this is going on, I'm pinging the server in the background, watching my WiFi connection monitor, or streaming music and everywhere aside from FFXIV experiences absolutely no issues. Really hope there is a fix soon.