Thank you for the question! It looks like you are trying to connect with a Monoprice Mini V2. This machine is peculiar and requires some special settings when connecting. The folks over at the unofficial Monoprice Mini Wiki did a great job of explaining the process in gritty detail so I have included the link to that below.
https://www.mpminidelta.com/slicers/s3d
In short it seems that this printer requires the hardware of software flow control options to be enabled to currently communicate properly. Please let me know if you have any other questions.