So, anyone know what's causing this? I'm getting a similar issue.

I can't access some zones, the connection just times out and I disconnect, and then if I try to log back in I can't. If I switch to my mobile connection I can log in, move, and then switch back to fibre and I'm fine unless I re-enter the same zone. The zone (or zones) will be off limit for a day or two, then it randomly switches to different zones.

Yesterday and today, I can't access Western Adoulin but I'm fine now I've zoned to Ceizak. A few days ago it happened when I entered Ambuscade, and last week I couldn't get in to the Shrine of Ru'Avitau. As mentioned, this is resolved as soon as I switch ISP so thought it was something at their end rather than an SE issue. UK based, is anyone outside of UK experiencing this?