Other browser extensions, particularly AdBlockers or other video downloaders, can conflict with IDM. Try disabling all other extensions temporarily. Refresh the YouTube page.
The most common reason for IDM failing on YouTube is a disabled or broken browser extension. Without the "IDM Integration Module," the software cannot communicate with your web browser. Open your browser’s Extension or Add-ons manager. Locate "IDM Integration Module." Toggle the switch to "On." internet download manager not downloading youtube videos
If a newer version is available, download and install it immediately. Restart your browser after the update completes. Check File Type Associations Other browser extensions
If it’s an AdBlocker, you may need to "Whitelist" YouTube or IDM within that extension's settings. particularly AdBlockers or other video downloaders