Mac Screen Sharing Session was Denied or Unsupported

If you attempt to connect via a shared session as a guest, the user on the remote Mac needs to accept your request:

If the user hits Cancel, you will not be able to connect. Selecting Share Screen will grant you access so you can share a screen session.

Enable Shared Screen Sessions

Another cause for this error is that shared sessions are not enabled on the remote Mac:

On macOS 13 Ventura or later

1. Click this link to open the Sharing settings on your Mac
2. Click (i) under Remote Management (or Screen Sharing if enabled)
3. Click Computer Settings…
4. Enable Anyone may request permission to control screen

On macOS 12 Monterey or later

1. Click this link to open the Sharing settings on your Mac
2. Select Remote Management (or Screen Sharing if enabled)
3. Click Computer Settings…
4. Enable Anyone may request permission to control screen