screen – Chromecast via HDMI-> VGA adapter works after a few minutes of noise

I have a first generation cromecast that goes to an old VGA screen (eMachines LE1987) via an HDMI-> VGA adapter. The start screen of the cast does not show any problem, but when I start a cast, the screen shows snow noise and the audio is just a digital pop for a minute or two. After a while, the cast suddenly appears good and lasts until you switch to a different application to cast. In Google, I see that the Chromecast would not be expected to work through a VGA adapter because HDMI is encrypted to prevent copying (HDCP), and both parties have to be licensed to decode the signal. But if that's the problem I'm having, I would not expect it to work. Is HDCP actually my problem? If so, why does it work after a few minutes? And is there any way to eliminate or shorten the wait?