Why do I get nsurlerrordomain 1200 and 1004 Nabu Casa

I have a raspberry 3B+ in my campervan with HA running from an ssd drive. Core 2023.12.3 Supervisor 2023.12.0
During the fall, it has started to get nsurlerrordomain 1004 and nsurlerrordomain 1200 when I try to connect via the app on my iPhone locally and remotely. cannot connect via web browser on iPad or iPhone. Had a similar problem when I ran DuckDNS, and got the tip to run Nabu Casa instead. Which has worked stably until late summer.
After restarting, it can work for 5 minutes - a week or so. Lately, it’s more like 5 minutes - some days.
Can the router set it up somehow? Have a Teltonika Rut11X which is connected via 4G
Anyone have any suggestions for a solution?