Seeing "Call Failed" or having your Galaxy S25+ drop calls constantly is a major headache. This usually means your phone is struggling to maintain a proper connection to your carrier's network. The cause can be anything from a weak signal to a minor software hiccup in Android 15 or One UI 7.
Let's start with the quickest fix, which often resolves the issue in under a minute.
Toggle Airplane Mode
This is the fastest way to refresh your cellular connection. Swipe down twice from the top of your screen to open the full Quick Settings panel. Tap the Airplane Mode icon to turn it on, wait about 10 seconds, and then tap it again to turn it off.
Your phone will reconnect to the network, which can clear out any temporary glitches that were preventing calls from going through.
Check Your Signal Strength
Weak signal is the most common culprit for failed calls. Look at the signal bars in the top-right corner of your screen. If you have one bar or see an "X," you're in a poor coverage area.
Try moving near a window or stepping outside. Buildings, basements, and rural areas can all block the strong signal your S25+ needs for reliable voice calls.
Force Restart Your Phone
A simple reboot can fix a surprising number of software-related issues. For the Galaxy S25+, press and hold the Volume Down button and the Side button (power button) together for about 10 seconds.
Keep holding until you see the Samsung logo appear on the screen, then release. This forces a clean restart and is different from just turning the screen off and on.
Review Do Not Disturb and Focus Modes
Check if you've accidentally enabled a mode that blocks calls. Swipe down to see your Quick Settings and look for the Do Not Disturb or a Focus mode icon (like Sleep or Work).
If one is active, tap it to turn it off. You can also go into Settings > Sounds and vibration > Do Not Disturb to see your schedules and allowed contacts.
Ensure Correct Date and Time
Incorrect time settings can sometimes interfere with network authentication. It's easy to fix by making sure your phone sets the time automatically.
Open Settings > General management > Date and time. Make sure the switch for "Automatic date and time" is turned on. This syncs your phone with your network's time.
Check Your Blocked Numbers List
It's worth a quick look to make sure you haven't blocked the number you're trying to call, or that your calls aren't being blocked universally. Open your Phone app and tap the three-dot menu in the top right.
Go to Settings > Block numbers. Review the list and remove any numbers that shouldn't be there by tapping the trash can icon next to them.
Verify Mobile Data and Network Mode
First, ensure your mobile data is enabled. Go to Settings > Connections > Mobile networks and make sure "Mobile data" is switched on.
While you're there, tap "Network mode." Try switching from "5G/LTE/3G/2G (auto connect)" to just "LTE/3G/2G (auto connect)" for a few minutes. Sometimes the 5G radio can have handoff issues that affect call stability, and this is a good test.
Update Your Carrier Settings
Carriers occasionally push small updates that improve network connectivity. These usually install automatically, but it's good to check.
Connect to Wi-Fi, then go to Settings > Software update. Tap "Download and install." If a carrier settings update is available, it will often be included here or will prompt you separately.
Inspect Your SIM Card
A loose, dirty, or faulty SIM card is a classic cause of call failures. You'll need the SIM ejector tool that came with your S25+ (or a small paperclip).
Gently push it into the tiny hole on the SIM tray to eject it. Remove the SIM card, wipe the gold contacts gently with a soft, dry cloth, and reinsert it firmly. Make sure the tray is fully seated when you push it back in.
Update Your Phone's Software
Software updates from Samsung frequently include bug fixes for network and calling issues. Make sure your S25+ is running the latest version of Android and One UI.
Go to Settings > Software update and tap "Download and install." It's best to do this while connected to Wi-Fi and with your phone charging.
Reset Your Network Settings
This will erase all your saved Wi-Fi networks, Bluetooth pairings, and cellular network preferences, but it won't touch your personal data like photos or messages. It's a powerful fix for persistent connection problems.
Go to Settings > General management > Reset. Tap "Reset network settings" and confirm by entering your PIN or password. Your phone will restart and you'll need to reconnect to Wi-Fi and Bluetooth devices.
Contact Your Mobile Carrier
If you've tried everything here and calls are still failing, the problem is likely on your carrier's end. There could be a local tower outage, maintenance, or an issue with your specific account.
Call their customer service from another phone if possible. Ask them to check for outages and to reprovision your line on their network, which is like refreshing your account from their side. They can also test your SIM card's health and send a replacement if needed.