WMS/WMTS on ArcGIS Online

Is anybody else having any issues with adding WMS/WMTS services to ArcGIS Online? I am able to add a WMS service and it appears in the content but no imagery is shown. I have no issue with adding these WMS/WMTS to QGis, ArcPro, or ArcGIS Portal running on Azure.
Thanks,
Christian

ArcGIS Online has (since about a year) an issue with WMS sources, that are not listed as under “specific domains”, see how to work around this:

We informed ESRI about it a while ago, but did not hear from them.

Thanks for the info Grega!

I am running into a similar issue now with ArcGIS online. I have added the Sentinel Imagery as a WMTS layer item in my AGOL account and am able to view the data in the old AGOL viewer but not in the new AGOL viewer. I have added https://services.sentinel-hub.com in the Trusted Servers and Allow Origins security settings in our AGOL account but that didn’t make a difference, still not showing up in the new AGOL viewer. I tried troubleshooting this with ESRI and they suggested this may have to do with the ArcGIS Javascript API version supported between the two AGOL map viewers, but not sure if that has anything to do with it or not. Happy to provide any additional information or details.