I hooked my Roku up an old computer monitor

I hooked my Roku up an old computer monitor using an VGA to HDMI adapter picture shows fine Netflix comes on but after I press play the screen turns blue and only the captioning shows but when I shuffle from scene to scene I see the little thumb nails but the big screen is blue can anyone help me?
Please help.

I didn’t find the right solution from the Internet.
healthcare product marketing

Thank you for your post
Let me say you that this forum is about Zabbix Network and IT infrastructure monitoring and controlling system.
So i think that here is not a good place for your question because your question is about hardware and this is not related to topic of this forum

Thanks and best regards