Kind of weird problem tbh, are u sure that u refreshed the trackbase tracker as it isnt real time update there. Considering u could try to connect when there's at least 10-15 slots free, so it would definitely be free to connect and cross that issue out. Checking now on the HLSW, the Jay1 is on 36/51 capacity, so if u would be able to connect during these later hours when the server isnt particulary full and see if the problem perssist.
FA1 - 188.8.131.52:27960
Silent 1 - 184.108.40.206:27960
I assume dare can check if there's any infos when u connect towards the server, if not then i assume he will have to do some deeper check into that, as i haven't seen any similiar problem like this and there isn't any other errors showing up, only that server is full, even if u do /reconnect ?
Can u also provide server nick u are connecting with?