If you have created a hosted feature service with ready only rights (only with export data option) and need to access it in QGIS, the below mentioned steps can be used if the criteria matches:
Service was shared with group.
One user of the group tried to open this service in QGIS.
It was added as ArcGIS REST server connection with credentials but they get error 499.
This issue can be resolved by sharing the service publicly. However, if we do not want to share a service publicly. We can follow the steps mentioned in the article below.
Securely accessing ArcGIS Online (AGOL) and enterprise ArcGIS Portal sites through QGIS (2022 update!) [non esri link]
https://north-road.com/2022/09/16/securely-accessing-arcgis-online-agol-and-enterprise-arcgis-portal...
