Some devices are not getting synched

Hi, I’ve an application which is using sync gateway and it has very interesting problem. Although the same apk has been installed on 5 different device only 1 of them is getting synched properly, the other ones dont get synched. How such thing can be possible? I even set the time zone of each device to be same each other. I really stucked, at somewhere Im doing something wrong but can not find at all. please show me a way.

NOTE: After 1 day, the other devices started getting synced. I dont have any idea why it started after 1 day… Does not sync gateway open different processes or channels for every different device to be synced? Im really confused because again 1 same apk, 1 same network, 1 same wifi, 1 same server and only 1 of them was getting synced, then after doing nothing they also started to be synced 1 day after.

Are the devices authenticating as the same user?

Are the devices logging any warnings or errors?

On Sync Gateway are you seeing logs about the HTTP requests from all the devices? When a device starts a pull replication you should see a GET to a path with _local in it (and it’s OK if this returns a 404), followed by a GET of /dbname/_changes.