As you may have noticed, we've gotten rid of the need to sign in to our forums seperately from the main site and implemented a Single Sign-On system. This is a great new feature and we hope that the added convenience it provides allows for a much better overall experience while using our various properties (the main site, Community site, these forums, etc.).
Unfortunately, it doesn't always work out that way. We've gotten a few reports of people having trouble logging into our new forums; the most common scenario seems to go something like this:
If this is the type of thing you're experiencing it is, in all likelyhood, an issue with cookies. As such, the best solution is to try clearing all cookies for the "infragistics.com" domain. If you don't have an easy way to delete domain-specific cookies (such as the Web Developer Toolbar), the easiest thing to try is to simply going back to the main site, logging out, then trying to login again. Hopefully, your cookies should be established correctly this time and you won't have any more problems. Try heading back over here to the Forums once again and see what happens.
If you continue to have problems, your scenario is different from the one I described, or you just don't care to go through the trouble of messing with your cookies, feel free to shoot an email to me at Infragistics Webinary and I'll be happy to help you out.
I was having this problem. Logging out and then back in fixed the problem for me.
Just an update: we have recently pushed updates to the main site (which we use to authenticate Forums users) which should alleviate these issues. If you are experiencing problems from now (Nov. 16th, 07) on, please shoot me an email directly at Infragistics Webinary and I'll make sure you get taken care of.