It may depend on the kind of service it is, but generally you can do that from ArcGIS Server Manager, typically found at your-org-url/server/manager
You can also stop services on ArcGIS Server Administrator Directory page
"FQDN/ name of your web adaptor/admin"
Choose the services you want, and click on them, and scroll down "stop"
I am not administrator of the Portal. Is there a way to log in as a publisher like in ArcMap and stop/restart a service?
I need to stop a portal item, a feature layer.
The service is a feature layer pointing to a feature class.
Hello Jose, apologized for the late reply, you can request a login from the administrator for ArcGIS Server Manager, https://enterprise.arcgis.com/en/server/latest/administer/linux/managing-users-in-manager.htm
You can just delete and republish the feature layer, as a workaround.