Steps to reproduce:

1. Open the execution server.

2. Type the correct scheduling service URL without HTTP.

3. Click the OK button.

Expected: To throw some user friendly message that you should type the URL with HTTP.

Actual: It leaves the URL blank and the execution server stops working. If you restart it it trows the attached exception.

The workaround is to open the config file in C:\ProgramData\Telerik\Configs and fix the URL manually.