Videos are postage stamp size on Mobile

I’m having trouble with videos that are not in a gallery displaying the normal size when viewing on mobile phone. I put the video in a flex and did not adjust the size of the flex or adust the default size of the video. It displays correctly on a desktop but displays very small on an iphone. I tried these settings and many others. I copied and pasted settings from Multithemes. Wonder theme and that didn’t work either.