Two rules to make sure you achieve smooth, successful (& slotted) posting...
1. Make sure the URL you use to visit the forum has the "www" in the address. I.e.
this link, rather than
this link.
2. Make sure you click the "remember me" button when you login.
Top tip! If you change the style you browse the forum in your User CP, from Ceroc Orange to, say, Metallic, you'll notice if you get logged out much sooner than otherwise.