I am no longer able to see Marketplace. It says an error has occurred please try later. This is now happening for a month?
From Facebook Help Center:
Marketplace isn't available to everyone right now.
If you don't see the Marketplace shortcut on Facebook.com, try visiting Marketplace from this link.
As mentioned on official page that marketplace is not available to everyone right now, so try login visiting given link. If it does not open for you means it is not available to you.