Hello
The issue you’re experiencing, where the Windows Boot Manager appears every time you restart your server, might be due to the boot settings in your system configuration. Here are some steps you can follow to resolve this issue:
Right-click on This PC and select Properties.
Click on Advanced System settings.
Under Startup and Recovery, click on Settings.
In the System startup section, uncheck the option "Time to display list of Operating systems".
Set the Time out to '0’.
Click Apply, then OK, and finally Restart your system.