Messages Stuck in Pending State - SMS Gateway (Local Server)

[juretopolak]

Hello.

What could be the reason that messages are being stuck in Pending state (local server)?

There are no enabled limits or delays, and usually, messages are sent instantly.

However, after a period of inactivity (e.g., overnight), messages frequently fail to send and remain in the Pending state (not sure if this is the reason).

Observations

• Manual SMS sending from the device works instantly.
• Factory reset performed on the phone, with only SMS Gateway App (v1.33.1) installed, but the issue persists.
• The device in use is an older Android phone (Mi A2 Lite).
• After restarting the device or interacting with it (offline, online, disabled local server, enable back, restart app, etc...), messages sometimes resume sending.
• Checked for app limits or delays. None enabled.

Are there known issues with Mi A2 Lite or older Android devices regarding SMS Gateway performance?

Could Android’s battery optimization or something similar be causing this issue?

Are there any recommended debugging steps or workarounds to prevent messages from getting stuck in Pending?

Any insights or suggestions would be appreciated. Thanks!

System health:

{
  "messages:failed": {
    "description": "Failed messages for last hour",
    "observedUnit": "messages",
    "observedValue": 0,
    "status": "pass"
  },
  "connection:status": {
    "description": "Internet connection status",
    "observedUnit": "boolean",
    "observedValue": 1,
    "status": "pass"
  },
  "connection:transport": {
    "description": "Network transport type",
    "observedUnit": "flags",
    "observedValue": 4,
    "status": "pass"
  },
  "connection:cellular": {
    "description": "Cellular network type",
    "observedUnit": "index",
    "observedValue": 0,
    "status": "pass"
  },
  "battery:level": {
    "description": "Battery level in percent",
    "observedUnit": "percent",
    "observedValue": 100,
    "status": "pass"
  },
  "battery:charging": {
    "description": "Is the phone charging?",
    "observedUnit": "flags",
    "observedValue": 2,
    "status": "pass"
  }
}

[capcom6]

Hello!

Thank you for the detailed report.

Could you please provide more details:

1. Did your messages contain a single recipient or multiple recipients?
2. Did you explicitly specify the SIM card number?
3. Is there anything noteworthy in the logs after restarting the app with Pending messages in the queue?

Regarding your questions:

1. At this point, I don’t see any obvious reason for this behavior. One possibility is that the sending task might be falling into a retry loop for some reason. The logs could provide helpful insights.
2. I’m not aware of any specific issues like this with older devices.
3. I don’t believe battery optimization is the cause, especially since restarting the app doesn’t consistently resolve the issue.

[juretopolak]

Thanks for the quick response!

Sure!

1. All messages have only one recipient.
2. I didn’t specify the SIM card number.
3. There are some errors in the logs right now. I don’t think I noticed them before. The webhook logs for system pings are “rotating” older logs. Could this error still be related to my issue?

I’m integrating SMS sending through the SMS Gateway app into my web app, which will have its own queue. The app will send POST requests for each message (with dynamic content) and track their statuses using webhooks.

I plan to send about 5 messages per minute, but I’m concerned they might get stuck in Pending status.

Can I expect any issues when sending, let’s say, 10,000 messages?

Especially considering the app is running on a less powerful Android device?

Thanks!

[capcom6]

You may encounter issues related to the Android OS itself or your carrier's terms of service with this amount of messages. You can find some advice on how to avoid these issues in the FAQ: here and here.

The app doesn’t require a lot of resources, especially if you’re not using end-to-end encryption. Are you using encryption? I believe the current issue isn’t related to the device’s performance.

I’ve prepared a new version of the app with additional logging. Please install the APK from the #202. When the issue occurs again, take the logs via the API starting from the last successful message. Since the logs may contain personal information, you can send them to me at [email protected].