Posting a kayak for sale

I am trying to post a used kayak for sale but I keep getting a message ‘invalid post’. Does anyone have suggestions for how to resolve this? Thanks

I assume you are trying to post it to the classifieds section of this site (Buy & Sell Paddling Gear | Paddling.com)?

yes, that is correct

What are you trying to sell and where are you?

Delta Traverse Tandem, 17.5T. I’m in Portland, Oregon