I´m trying unfederate Arcgis Server from Portal by https://portal.domain.com/arcgis/sharing/rest/
But in webpage don´t appear information about Arcgis Server federated look below:
There is no server option...
Why this happens?
If you wanted to unfederate from sharing/rest I recommend you do it with the assistance of an ESRI support analyst on the line as the consequences are irreversible. However, if your content is already lost and your federation is already broken. When you get to sharing/rest follow the steps outlined below.
Login in the top right corner.
Click the home button in the top left.
Scroll all the way to the bottom of the page.
Click the server ID listed.
This will make the unfederate button appear.
You are now unfederated!
As a side note. For whatever reason you are Unfederating this only removes the federation from the Portal. If you want to clear the federation from both server and portal, you should unfederate in portal admin as it clears the federation for both applications. If this isn't working you can do it the above referenced way and then go in and manually unfederate Portal from server admin by logging into server admin, clicking on security, clicking on config. There you will find a drop-down change portal to GIS_Server. Once you do this both applications will no longer be federate