The same thing happens to me when trying to access my university website (regardless of my wifi connection.. it happens wherever my touchpad is connected). I've posted this in another area, but curious what site the original poster is trying to log in to.
The site that behaves like described above (log in with correct credentials > no error or anything > brings you back to log on page) is fullerton.edu
Try refreshing the login page after logging in. I notice sometimes on these forums that it doesn't show me logged in until I navigate to any forum page or topic, or until I refresh the page. But I'm definitely typing this from my touchpad's browser. If that doesn't work, clear the cache/cookies etc.
I have logged into these forums, Amazon, ESPN, and NFL, just off the top of my head. Ohh also some other random forums, registered and logged in from TP.
I love physical keyboards... but there is two devices that would make me consider a slab, one is something running a full version of Open webOS. The other is an iPhone!!!! HA HA just kidding (about the iPhone that is)...
I've experienced this as well, on a few other forums. I suddenly find myself logged out, and when I go to log back in, it acts as if I put in the wrong password, or just brings me right back to the login page, and I'm never able to successfully log in.