Hi if you have problem in data sending to server even if you have good signal you can change your settings under GPRS window,
1. find the records settings , from the record settings you can see the openlink timeout, response timeout and network ping timeout.
2. try to increase the parameter for the openlink timeout so the link between the device and server will increase the time duration
3. set your response time out to 10
4. dont forget to enable or set value to network ping timeout in this will prevent the closing of the link from your device to the server.
5. Make sure that you set your parameters correctly in the data acquisition this is very important parameter in saving and sending data.
FMB204 Data acquisition settings - Wiki Knowledge Base | Teltonika GPS (teltonika-gps.com)
6. make sure to that you have the latest firmware of your device.
FMB130 firmware errata - Wiki Knowledge Base | Teltonika GPS (teltonika-gps.com)
FMB204 firmware errata - Wiki Knowledge Base | Teltonika GPS (teltonika-gps.com)
I hope this will help. Regards