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Many Android devices have a built-in restriction that stops you from sending more than 30 SMS messages within a 30-minute window. When your gateway crosses that limit, Android shows a warning and can block further messages:
SMS Sync is sending a large number of SMS messages. Do you want to allow this app to continue sending messages?
Android warning that SMS Sync is sending a large number of messages, with Deny and Allow options
This is an Android safeguard, not a limit inside your CRM. You can raise it manually with a small tool we provide, so high-volume sending no longer trips the alert.
This changes a hidden system setting on your phone using Android debugging. It’s safe and reversible, but only do it on a device you own and control. A few manufacturer ROMs gate this behind an extra toggle - see Extra step for some phone brands.

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What you’ll need

  • The Android phone running your SMS gateway (Android 11 or newer for the Wi-Fi method).
  • A Windows, macOS, or Linux computer.
  • One of these connection methods:
    • USB (recommended): a USB cable, and (on Windows) a working USB driver for your phone. If Windows doesn’t recognize it, install your manufacturer’s OEM USB driver.
    • Wi-Fi (alternative): the phone and computer on the same Wi-Fi network (Android 11 or newer). No cable or drivers needed.
You do not need to install ADB or any developer tools yourself. The tool below downloads everything it needs automatically.

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Step 1: Turn on Developer Options

The tool needs Developer Options, which is hidden by default.
1
Open Settings and search for Build number (or Version number).
The exact location differs by brand, so searching is the most reliable way to find it. It’s usually under About phone → Version.
2
Tap Build number 7 times in a row. You’ll see a message confirming that Developer Mode (or Developer Options) is now enabled.
Android Version screen showing Version number and Android version
3
If prompted, enter your PIN / password. Some brands also ask you to sign in to your manufacturer account (Mi, Vivo, etc.) before Developer Options can be turned on.

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Extra step for some phone brands

Some Android “skins” gate the SMS setting behind one more toggle in Developer options. If you have one of these brands, enable it now so the change can take effect:
Enable USB debugging (Security settings). You usually need to be signed in to a Mi account with a SIM inserted for this toggle to be available.
Turn on Disable permission monitoring. Without this, ColorOS can silently block the command.
Enable USB debugging (Security settings). This may require you to be signed in to a Vivo account.
Usually works with no extra toggle. If the command is refused, check whether a Knox / work profile is active on the device.

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Step 2: Download and launch the tool

Pick the tab for your computer’s operating system. The tool downloads the required Android platform tools automatically on first run.
1
Download and unzip the Windows tool. Keep both files in the same folder - the .bat launcher needs the .ps1 script next to it.

Download the Windows tool (.zip)

Contains Raise SMS Limit.bat and raise-sms-limit.ps1.
Extracted sms-limit-windows folder containing Raise SMS Limit.bat and raise-sms-limit.ps1
2
Double-click Raise SMS Limit.bat. A terminal window opens and downloads the platform tools on first run.
3
Continue with Step 3: Connect your phone when the tool asks how to connect.

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Step 3: Connect your phone when the tool asks

The tool asks how you want to connect your phone:
We recommend the USB method - type 2 and press Enter, then follow the USB tab below. (Wi-Fi works too if you’d rather not use a cable.)
1
On the phone, go to Developer options → USB debugging and turn it on.
USB debugging toggle enabled in Developer Options
2
Plug the phone into your computer with a USB cable, then press Enter in the tool.
3
Look at your phone screen: tap Allow on the Allow USB debugging? prompt. Tick Always allow from this computer first if you’d like to skip this next time.
Allow USB debugging prompt on the phone showing the computer's RSA key fingerprint
If the phone never appears, the cable may be charge-only or Windows may be missing the OEM USB driver for your phone. Install your manufacturer’s driver from Google’s list - Install OEM USB drivers - then reconnect. Or use the Wi-Fi method instead, which needs no cable or drivers.

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Step 4: Confirm the new limit

Once connected, the tool writes the new values and prints Done. New limit: 10000 messages per 15 minutes.
Windows command prompt showing the new SMS limit set to 10000 messages per 15 minutes

Windows

macOS Terminal showing raise-sms-limit.sh writing the new SMS limit values

macOS / Linux

A new limit of 10000 messages per 15 minutes is high enough that normal gateway sending will no longer trigger the warning.

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Confirm it worked

Send a batch of messages from your CRM as you normally would. The “SMS Sync is sending a large number of SMS messages” warning should no longer appear. The change stays in place until the phone is factory reset. If you connected over USB, you can unplug the cable straight away - it’s only needed while the tool runs.

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If it doesn’t work

If the tool reports “The setting did not stick,” or you saw a SecurityException about WRITE_SECURE_SETTINGS:
  • The adb shell isn’t privileged on this ROM. Enable the brand-specific toggle for your device (for example, ColorOS’s Disable permission monitoring, or USB debugging (Security settings) on Xiaomi/Vivo), then run the tool again.
  • A few Samsung and Xiaomi ROMs enforce their own SMS guard that overrides this setting entirely - on those devices this method can’t raise the limit.
  • If pairing or connecting failed, re-open the phone’s Wireless debugging screen for fresh values (the code and ports rotate) and try again.
If you’re still stuck, reach out to support below and let us know your phone brand and model.

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Support

If you need help increasing the SMS limit: