Whats up with Walmart Online?

Saw this on Walmart online and wanted to get it. Everything was smooth, I bought it for $16 +tax. A few moments, probably even less than a minute, later I get a notification saying the order was canceled. When I go back to buy it again, for the second time, the price went up to the basically MSRP of 21 or 22. I know that isn't MSRP but that's what they are going for literally everywhere. Walmart, what the hell is going on? I say 'Walmart' but yall tell me if they are just trying to get me to...