Problem on Pivoting via sock proxy

I am trying to do some recon on an internal network via Pivoting. At first, the connection is ok but later on this error occurs

I tried to do internal network enumeration which is not part of the solution. It won’t let me perform any of enumeration on open ports of the internal network IPs via pivoting. That made me think that the web-based labs are designed in a way to limit users to only follow the solution if they get stuck. So if a technique is not covered in the solution, it won’t work.

If you are experiencing an issue while following the solution, then resetting the lab is an option.