Seeing a "Call Failed" message on your Samsung Galaxy S25 Ultra can stop you in your tracks. This usually means your phone is having trouble connecting to your carrier's network properly. It's often a quick fix related to your signal, a software hiccup, or a setting that got switched off.
Let's start with the simplest solutions that often clear up the problem in under a minute.
Toggle Airplane Mode On and Off
This is the quickest 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 only have one or two bars, try moving to a different room or near a window.
In some buildings, the S25 Ultra's antenna might struggle. If you see an "X" or "No Service," you'll definitely need to relocate to get a call out.
Perform a Force Restart
A simple reboot can fix a surprising number of software-related calling issues. For the Galaxy S25 Ultra, press and hold the Volume Down button and the Side (power) button simultaneously.
Keep holding them for about 10 seconds until you see the Samsung logo appear on the screen. This forces the phone to shut down and restart, clearing its memory.
Review Your Do Not Disturb and Focus Modes
Check that an active mode isn't silently blocking your calls. Swipe down to see your Quick Settings and look for the Do Not Disturb or a Focus mode icon (like "Work" or "Sleep").
If one is enabled, tap it to turn it off. You can also go into Settings > Sounds and vibration > Do Not Disturb to see if any schedules are active.
Verify Your Date and Time Are Correct
Believe it or not, an incorrect system time can mess with network authentication. Open Settings > General management > Date and time. Make sure the "Automatic date and time" switch is turned on.
This lets your phone sync the correct time from the network, which helps maintain a stable connection for calls.
Check Your Blocked Numbers List
It's worth a quick look to ensure you haven't accidentally blocked the person you're trying to reach. Open your Phone app and tap the three-dot menu in the top-right corner.
Go to Settings > Block numbers. Scroll through the list and if you see the number, tap the minus (-) sign next to it to remove it from the block list.
Ensure Mobile Data and Roaming Are Enabled
While calls use the voice network, some carrier features rely on data. Go to Settings > Connections > Mobile networks. Make sure "Mobile data" is switched on.
If you're traveling, you might also need to enable "Data roaming" in that same menu, but be aware of potential charges from your carrier.
Update Your Carrier Settings
Carrier configuration updates are pushed out to improve network performance and fix bugs. These often install automatically, but you can check.
Go to Settings > Software update and tap "Download and install." While you're there, also check for any system updates, as they include important fixes.
Try Switching Network Modes
Sometimes, the 5G or LTE network in your area might have an issue with voice calls. You can try forcing your phone to use an older, but often more stable, network type.
Go to Settings > Connections > Mobile networks > Network mode. Instead of "5G/LTE/3G/2G (auto connect)," try selecting "LTE/3G/2G (auto connect)" for a while and see if your calls go through more reliably.
Inspect and Re-seat Your SIM Card
A loose or dirty SIM card is a classic cause of call failures. Grab the SIM ejector tool that came with your S25 Ultra and gently push it into the small hole on the SIM tray.
Pull the tray out, remove the SIM card, and give the gold contacts a gentle wipe with a soft, dry cloth. Blow any dust out of the tray slot, then reinsert the SIM card firmly and push the tray back in.
Reset Your Network Settings
This is a more thorough step that clears all your saved Wi-Fi networks, Bluetooth pairings, and cellular settings. It won't delete your personal data like photos or messages.
Go to Settings > General management > Reset > Reset network settings. Tap "Reset settings" and enter your PIN if prompted. Your phone will reboot 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 temporary network outage in your area, a problem with your account, or your SIM card itself might be faulty.
Give your carrier's customer service a call from another phone. They can check for outages, reprovision your line on their network, or send you a new SIM card if needed.
