Hi @Christopher ,
I am sorry to hear that you are facing this issue! I would recommend checking out the comments on this Reddit thread and making sure you don't have any special characters in the URL, if you have anything different from the example you posted.
Which guide are you following? There is also an example of this in the guide for configuring Chrome for Android devices that shows how you can add this from the admin center:
Managed Bookmarks: [{"toplevel_name": "My managed bookmarks folder" }, {"url": "baidu.com", "name": "Baidu"}, {"url": "youtube.com", "name": "Youtube"}, {"name": "Chrome links", "children": [{"url": "chromium.org", "name": "Chromium"}, {"url": "dev.chromium.org", "name": "Chromium Developers"}]}]
If this doesn't work, you may also need to check the event logs to get more details. (In the example in the linked blog, the OMA URI was not correct and the user was able to resolve the error by fixing it.)
Lastly, I would recommend visiting the official troubleshooting guide for that error, which states that in some cases this error can be ignored and will go away after the device checks in again