I've had this happen before, and honestly I'm not 100% sure what fixed it. It's working fine for me currently, however.

If it keeps happening, try deleting your web browser's cache/temporary files (make sure you don't delete your saved passwords, Autofill form data, etc. Resetting your cookies may be a good idea, but note it'll automatically sign you out of all websites you're currently signed into).

Also try using another web browser, if you have one. Google Chrome is what I'm currently using, but honestly any modern browser shouldn't have any issues...

You may have to allow pop-up windows for the website, also, seeing as how the Microsoft option opens a new window entirely.

Good luck!

I renewed my premium status on December 27, at which time I realized the trading function was down.

I consider myself fairly patient. But here it is, January 6, and I'm still unable to trade with others who have premium. When I try, I receive the following:

"There is currently a problem with the selected function. Use is restricted for investigation. Please check the player's site for details."

The servers just came out of maintenance earlier today, along with a patch.

1/3 the duration of my premium subscription being active, and I'm still unable to trade.

I don't really want the free triboost for the inconvenience, I'd simply like to know what's going on and when the trade function will be back? The game is over eight years old now, I find it a little difficult to believe it's still riddled with this many issues... it seems to be a constant thing, honestly.

Thanks for any info.