That is strange. Try wipe out and leave the “Configuration Path” empty to make sure the device not be provisioned or configuration overwrite by some server.
Also, open a HELPDESK ticket with Grandstream Support, and export CFG file and upload to the ticket.
This seems to be the configuration issue. Have you tried using different browser to log in and configure the device? What is the browser you are using right now?
Please work with HELPDESK support engineer to help resolve your issue. Worst case is RMA and swop the device, if HELPDESK support engineer confirmed this is not a configuration issue but a hardware defect.
Thank you for using Grandstream Access Control Products.