Problems in Traccar Server and Android devices

I’m doing some tests with Traccar Server but several problems appeared. I'm current running 8 android devices but they all have instability problems, besides they locations are not saved in the reports and delay of 20 min for positions in the map, the delay varies from 20 mins to hours.
I imagine that the problem must be in the code that I had to write to send the data to the traccar server , however it seems all right.

2016-02-15 12:16:04  INFO: [33A13D64] connected
2016-02-15 12:16:04 DEBUG: [33A13D64: 5055 < 10.0.0.108] HEX: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
2016-02-15 12:16:04 DEBUG: [33A13D64: 5055 > 10.0.0.108] HEX: 485454502f312e3120323030204f4b0d0a0d0a
2016-02-15 12:16:04  INFO: [33A13D64] disconnected
2016-02-15 12:16:04  INFO: [33A13D64] id: 1, time: 2016-02-14 12:14:23, lat: -20.45600, lon: -54.63889, speed: 4.6, course: 100.5

What code have you written? Are you talking about official Traccar projects?

First of all I'm Brazilian , sorry for my English.

Yes, I'm hosting a Tracar Server (Version 3.4), I opened the ports correctly and follow all the instructions. The server is online but I'm still having problems with the devices.
I have written a code to send the coordinates to the Traccar sistem.
I know you have an app for that,I try to use but is not working, maybe I need help if that too, but my first intention is to not use the app. I need a way to sent the
informations by myself to the sever, is this possivel right? It's wornking but I have the instability problems and the delay.

http://imgur.com/T7dZsMo

The 454920 is the APP in a android device.

The "Válido" field is "No" , that is worrying me ,should be " yes" ?

It is definitely possible to send location to the server yourself.

You can ignore "valid" field. There was an issue with Traccar server. It will be fixed soon.

As for your app problem, please read following page:

https://www.traccar.org/troubleshooting/

ah ok thanks.
it's possible to send messages to the server using a socket-based communication protocol?

All protocols that I know are using sockets. What exactly do you mean?

To the web server, i'm using http.

Now I'm completely confused. Can you please provide more details on what you are trying to achieve.

Sorry for that. Ok i'm going to try by more specific,first of all the app is working on the android device, so that problem is solve. I'm working on a project to monitor some mobile devices (about eight) while they move across the city, but they make some important stops in the way and I need to see the moment they start to move again. If the app i can see the log report but in the web interface the real time tracking have some issues, like the historical data in the web interface for the the day is not informed and the real time tracking is not working, the device is moving but the point isn't, but later (10 to 15 min) they appear in the final location, this short period of time is important.

Are you using official Traccar Client app for that? If locations are missing, most likely it means that device couldn't get a fix then. What location provider are you using?