Chrome Version       : 54.0.2840.79 beta (64-bit)

(Google Chrome OS)

What steps will reproduce the problem?
(1) Open network settings, 
(2) select a mobile data network,
(3) select "Other..." for `Access point name,`
(4) enter a value and press save. 

What is the expected result?
The mobile data connection should save that configuration and attempt to connect with the prescribed settings. 


What happens instead?
The settings are initially shown on the select/drop-down menu, but an error in console reports that the save is unsuccessful and attempting to connect and then re-opening the network settings window shows that the settings have been discarded and presumable were not used to connect. 

Please provide any additional information below. Attach a screenshot if
possible.

The console error is as follows:

Unchecked runtime.lastError while running networkingPrivate.setProperties: UnknownNetwork

I tried to debug a bit and run through the process manually with the same result:

(1) chrome.networkingPrivate.getNetworks( ... ) to get the GUID for the cellular interface
(2) chrome.networkingPrivate.getProperties( [GUID], ... ) to review the properties for the connection
(3) Storing and modifying the properties for the connection, {"Cellular": {"APNList": [ ... , {"AccessPointName": "..."}]}}
(4) chrome.networkingPrivate.setProperties( [GUID], [ModifiedProperties] )

The output from the last command is the same as when using the UI to run the process, error `Unchecked runtime.lastError while running networkingPrivate.setProperties: UnknownNetwork`