Friend referral codes do not work

[Sj]

Hello, the referral codes posted here are not working at checkout, message pops up - code is not valid or expired. I tried a bunch of code from today, and 2 of them being within a minute of being posted, and having 1 and 2 views respectively. But still they came out as expired or not valid. Any help would be appreciated since otherwise, the trust on this forum and codes posted is shaky! Thanks for looking into this!