You don't need to reboot to change your pool settings.
Just be patient enough when you set the pool configuration and click submit and apply, that the messages that it is updating your /etc/config/miner.conf or something are gone before you switch windows. It's a long shot, but happened to me as well in frustration.

Second option is ssh into the miner and configure the pool settings yourself in /etc/config/miner.conf

But there could a whole lot wrong, so as the poster above mentioned, show us your settings, maybe it's just a small mistake.