I've encountered this problem today, and there are a lot of same issues on the platformio-vscode-ide.
After some diggings, this may due to the confliction of port range settings.
The major problem there is:
const HTTP_PORT_MIN = 45000;
const HTTP_PORT_MAX = 45999;
this range is conflicted with WSL on [44619, 48715] (4097 ports) if WSL is running in mirrored networking.
change this range may fix the problem for many users.