Hi there! I see you're getting an "invalid" error when pasting a YouTube link into the Smart Noter app. Let's get to the bottom of this together.

To start, can you tell me:
- What exact format does the YouTube link have? (Is it a full URL like https://www.youtube.com/watch?v=XXXX or a shortened link?)
- Are you copying the link directly from YouTube's share button or typing it manually?
- Have you tried using multiple YouTube links? Do all of them show invalid, or just certain ones?

Meanwhile, here are some quick checks we can do:

1. Check the YouTube URL format: The app typically requires the full, standard YouTube video URL. For example:
https://www.youtube.com/watch?v=VIDEO_ID
Links with extra parameters or shortened URLs might not be accepted.

2. Avoid spaces or hidden characters: Sometimes copying links adds extra spaces or invisible characters. Try pasting it into a plain text editor first to confirm.

3. Update the Smart Noter app: Ensure you have the latest version installed, as older versions might have issues recognizing newer YouTube URL formats.

4. Try pasting a different valid YouTube URL: To check if the problem is with the specific link or the app.

If after trying these it still says invalid, it could be an app-side issue with how links are parsed. In that case, I'd be happy to help you escalate it internally or provide any workarounds.

Let me know what you find or if you need any help with those steps!