Based on the information contained in the publicly shared file (Sync Problems - Google Drive), the mobile devices synchronize to a server which is located not by a static IP address, but rather utilizes a dynamic DNS service.
The log mentions activity (on this specific device where the log was obtained) on the 12th of February 2026 and last activity about 13th of March 2026 (give or take a few hours for time zones difference).
This can be explained by using a free account at the dynamic DNS service provider, which was restricted to 30 days/1 month grace period and disrupted further communication after the expiration of the free tier. This is consistent with @hamdan’s claims that:
- multiple modern devices (Android 16 based, and 2024 issue) experienced the issue,
- and that:
We have verified our server configuration, firewall settings, and network connectivity , and everything appears to be working correctly.
(@hamdan doesn’t describe what specifically was checked and how, but it is reasonable to expect that all of these checks were done on the server itself, leaving the dynamic DNS link out of scope).
This is also consistent with the fact that the domain was not accessible (in my trials) on the day the forum question was posted using a standard-issue browser and a laptop (leaving aside Survey Solutions mobile applications and any Android-related issues).
Public static IP addresses are available from various service providers for a cost of under ~4USD/month (and often cheaper in a package of other services). While Survey Solutions software remains free, spending a bit on the proper infrastructure and hardware setup can save a great deal of headache and troubleshooting in the long run.
In the absence of any other information from the user this is deemed the most likely cause. And if so, the recommendation can be formulated to set up proper static IP address for the server, acquire a domain name, and bind the domain name to the server IP address directly.
For more details, see post-installation configuration and other documentation pages as well as several earlier posts in this forum on public static ip-addresses, domain names, SSL certificates, HTTPS traffic and other relevant terms.
