You might be too new. See, community.frame.work/t/update-on-community-market-access/71850.
And are maybe using a “guest” account? I honestly don’t know what usernames which are “Guest#” mean. Perhaps just taking a system suggested username? Either way, I personally wouldn’t want to paypal money to someone with a random Guest#.
Ebay and reddit.com/r/frameworkmarket are also options.