PUP.Optional.PrxySvrRST is capable of changing the proxy server settings on an affected system. It triggers an action that disables the proxy, so that the user will have normal internet access again. Otherwise, if Malwarebytes Anti-Malware stops the process that is responsible for the proxy, the internet access could be broken.
You can read more about this registry key on the following blog posts:
Common Infection Method
You will find this detection mostly associated with adware.
Malwarebytes completely removes this threat. No further cleanup required unless you were using a proxy before you got infected.
A removal guide for Techsmart can be found on our forums.
To manually reset your Internet Explorer proxy settings, please check out this link from Microsoft Support.
You may find more specified detections for the same action, like for example: