HT802

It's very simple, on the ATA device you enter these info.

then you go to your fusion server and configure the device


you also have to double check that your provisioning is enabled on your server and matching your provisioning Auth info.

Good Luck

My best bet would be that this device is probably registered to Grant stream remote provisioning and therefore every time you save it and it resets it takes the configuration directly from Grant stream again

1st of all is this device a new device or you're bought this used if you bought it you wish that you have to ask the previous owner to release it if it can't can't be released then reach out to grand stream open a ticket they should be released for you
There is a way of downloading a configuration from fusion and uploading it to the device when you go to devices you select this device the drop down on the top right that were logged to drop to download the file and you can upload that but that's not goingna solve your problem if it's still a remote provision unless you figure it out the way put the sable remote provisioning on your device

I don't use Fusion provisioning at present, but use a bunch of HT802 devices with FusionPBX and they all work fine. I have seen the config paths not save when the firmware is old, or the device needs a reboot. Grandstream does not lock these addresses down that I have ever seen, neither on the phones nor the gateways. If you want to do it the manual way, you could try:

1. If you have any doubts about the configuration being messed up, do a factory reset. Methods to do this are listed in the manual:
2. Recommend you upgrade to the latest firmware if you haven't already -- there have been some nasty security and other bugs fixed in recent versions:
2a. To update the firmware manually, download the firmware from the above, then on the HT802 menus navigate to Advanced Settings, scroll all the way near the bottom, and choose Upload Firmware from local directory.
3. After the device has rebooted and you have confirmed it has the new firmware, set it up just like a phone:
3a. If you haven't already configure a normal extension in FusionPBX you want to use.
3b. On the HT802 navigate to the FXS port1 or port2 menus.
3c. Put in the Primary SIP Server address. If you have Fusion set up with a domain name, you must use that instead of the IP address.
3d. For the SIP User ID and Authenticate ID put the Fusion Extension you created, and the Fusion Extension password under Authenticate Password.
4. Scroll the bottom of the page and Apply. After a few moments check the Status page of the HT802 -- it should show Registered.

There are a bunch of other settings you can adjust, but the above are the most essential to make it work at least at a basic level. I've got the HT802's in use for analog phones, elevators, etc. Also tested them using analog fax machines (may be SIP provider dependent), and have only had trouble getting them to work with certain fire alarm systems so far. Oh if I remember correctly, I did have trouble with one elevator not hanging up properly and had to adjust the Loop Current Disconnect Duration to 500ms from the default 200ms.

I don't know if you're still having this problem, but I ran into this same issue the first time I tried provisioning an HT802. My issue was that I was selecting the HTTPS radio button *and* entering https:// before the URL. When I would save, it would revert back to "fm.grandstream.com/gs" since HTTPS was already selected and not needed in the address. If you were entering your URL as "https://pbx.yourdomain.com/app/provision", try entering as "pbx.yourdomain.com/app/provision".