Error type: "Forbidden". Error message: "Access Not Configured. YouTube Data API has not been used in project 548160373988 before or it is disabled. Enable it by visiting then retry. If you enabled this API recently, wait a few minutes for the action to propagate to our systems and retry." Domain: "usageLimits". Reason: "accessNotConfigured".

Did you added your own Google API key? Look at the help.

Check in YouTube if the id sagarmathatvnepal belongs to a username. Check the FAQ of the plugin or send error messages to support.