Seeing the spinning circle for a long time when placing an order or when enabling a token for trade may be due to low gas on the transaction. It may appear that the order is stuck.
Metamask processes all orders sent to the blockchain in order so if a transaction is slow it will slow down transactions that have come after it.
To see if you have orders that are waiting to process open Metamask and click on the sent orders.
Scroll back through orders to find the first order that is still waiting to be mined.
Click on "Retry with a higher gas price here" to pull up the Metamask confirmation window for the transaction.
At this point you can choose to submit the order with more gas and get it to go through faster or you can click reject to cancel the transaction.
Use https://www.ethgasstation.info/ as a reference for how much gas to us on the order. Click directly on the order to see the status of the transaction on etherscan.