As a buyer, you sometimes may not be able to start a trade with specific sellers for some reason and get the following message:

"You do not meet the requirements set by the vendor", "Offer not found" and more.

This is not a technical error — This happens as the offer owners may set the following restrictions for their potential trade partners:

• Verification of phone, email, ID 
• Visibility only for users marked as "trusted"
• A minimum of successful trades required
• A limit for the amount of money a new account is able to trade
• Geographical blocks for certain countries
• Proxy/VPN limitations
• User has blocked you due to any personal reasons