A few questions.Your Internet Service?
What 'OS' (Operating System) are you using?
Dose this happen if -
you keep the the same internet window and change websites then return to TFM?
you close the internet window that you loged in with and open a new internet window?
you closed and powered down your computer, restarted computer(warm reboot or cold reboot) and open new internet window?
The reason for the questions is to debug the problem.