Cameras are missing in Arnold render view in Maya

Issue:

At the attempt to render camera views from cameras in a Maya scene file with the Arnold render view, the cameras are missing from the available cameras rollout menu in the Arnold render view.

Causes:

Cameras are assigned to hidden display layers.

Solution:

1. Check if cameras are assigned to display layers.
2. Remove the assigned cameras from the display layers or set the display layers to visible.

Note: It is not recommended to control the visibility of cameras by display layers. The camera object visibility can be controlled by selecting the camera in the Outliner and un-checking the function Object Display > Visibility in the Maya Attribute Editor:

Source: Autodesk