Rapsberry Pi 4, MagicMirror v2.29.0

I have a week-old install working for all modules except MMM-EmbedURL. I am trying to get two, local ip cams to display a feed over http. These feeds work fine in the Chromium desktop browser. Here’s an example of a URL:

http://10.0.0.51:50081/ui3.htm?t=live&cam=Doorbell&maximize=1

I have tried other URLs, including the examples, but nothing shows up, not even an error. This is the last module to load for me, and no errors are present for any module. There are not any other broadcasts or messages related to this module afterwards. The header used does appear, confirming the module is loaded.

[LOG]   Connecting socket for: MMM-EmbedURL
Sockets connected & modules started ...

In case there are any known issues with other modules, here’s a list of what’s installed and working, across 4 different pages with MMM-pages:

WallberryTheme
WB-clock
WB-weather
MMM-CalendarExt3Journal
alert
updatenotification
clock
MMM-homeassistant-sensors
MMM-CalDAV
Pinfo
calendar
MMM-Pir
MMM-MoonPhase
MMM-NHL
MMM-MyStandings
MMM-EasyPix.
MMM-BGSS_1 (copy/tweak of MMM-BackgroundSlideshow)
MMM-GroveGestures
MMM-NotificationTrigger
MMM-EmbedURL

Here’s the top of my config.js, as well as the relevant module configuration:

let config = {
        electronOptions: {
                webPreferences: {
                        webSecurity: false,
                        webviewTag: true,
                        },
                fullscreen: true,
                alwaysOnTop: true,
        },

and

{
                       module: "MMM-EmbedURL",
                       position: "upper_third",
                       header: "Embed-URL",
                       config: {
                               updateInterval: 120,
                               embedElementType: "webview",
                               attributes: [
                                       "frameborder=0",
                               ],
                               embed: [
                                       "http://10.0.0.51:50081/ui3.htm?t=live&cam=Doorbell&maximize=1",
                                       "https://www.youtube.com/embed/dIHr96KqfDI",
                               ]
                       },
               },

I’d appreciate any help on this, and let me know if there’s something else I can add or provide to resolve.