I tried to follow these steps, to secure an Experience via AGOL. FAQ: Is It Possible to Create Custom Widgets in ArcGIS Online?
I set the config.json: clientId, that I obtained by creating a application in my organisations Agol, and I set as portalUrl the Url of that Agol.
"attributes": {
"portalUrl": "https://*****.maps.arcgis.com",
"isWebTier": false,
"clientId": "ZZwh1GZDX2*****",
The experience makes requests to and receives {
"error": {
"code": 405,
"messageCode": "GWM_0005",
"message": "Method not supported.",
"details": []
}
}
and
https://****.maps.arcgis.com/sharing/rest/oauth2/platformSelf?f=json
and receives
{
"error": {
"code": 403,
"messageCode": "GWM_0003",
"message": "You do not have permissions to access this resource or perform this operation.",
"details": []
}
}
I assume these two failed requests stop the OAuth attempt. Is there anything else that you have to configure in your arcgis online instance?