The US trade-talk team didn't get the message that China was sending in Shanghai.

A picture tells a thousand words!  How true it is!

The ancient Chinese poetry on the wall had a hidden message which China was trying to send to the US team but the US team didn't understand the implied meaning because there was no Chinese expert on its team.

The poetry was depicting a magnificent mountain and the cloud came along to create a more picturesque view.  The cloud could come and go but the mountain would still be magnificent and picturesque as ever without the cloud.

The implied meaning from the poetry was that China didn't care about whether the US team did come for the trade talk because China would still be doing fine without the trade deal.

The US team didn't understand the poetry on the wall and the meeting broke down in less than 4 hours because it continued with its unreasonable US demands.