Go to the Settings app, switch Airplane Mode to off, then switch it back on 30 seconds later. If that doesn’t work, go to Settings > General > Reset and select Reset Network Settings. You also might want to try powering down your iPhone and turning it back on. Select the Voicemail tab, then select Set Up Now. Note: Alternatively, you can set up voicemail by selecting the Phone app then pressing and holding the 1 key. If prompted, enter your voicemail password then follow the prompts to set up your voicemail. Go to Settings app → Tap on Cellular Data → make Turn Cellular data ON. If it’s already enabled, then make the turn-off and back on again and however, you have an issue regarding voicemail then try next way.
There are two steps you have to do before you can use voicemail on your phone. The first is that you have to add a voicemail number. This number varies by country and also your service provider. If you’e use AT&T, you can follow AT&T Galaxy S21 voicemail setting. Open the “Phone” app. Tap the 3 dots on the top right. Tap “Settings“. Tap “Voicemail“. Tap “Voicemail Settings“. Take note of the green number below “Voicemail number“. Go back to the dialer and enter the number from Step 6 (including the *). Press the green phone button. The voicemail number has been set. Return to the Start screen.

Just NowSet up Visual Voicemail. If your carrier supports Visual Voicemail, you can set it up with these steps: Go to the Phone app, then tap the Voicemail tab. Tap Set Up Now. Create a voicemail password, then tap Done. Enter your password again to confirm it, then tap Done. Select Custom or Default. If you choose Custom, you can record a new greeting.
Follow the instructions and press that number. You will be asked to delete your current Voicemail greeting. Click on the ‘Yes’ button that appears on the screen if you want to remove that. You can save your new recorded Voicemail greeting or can use the default recorded option. From the home screen, select the Phone app. Note: Alternately, you can set up voicemail by selecting the Phone app then selecting and holding the 1 key. Select Keypad, then select the Visual Voicemail icon. Select Start. Select Ok. From any Home screen, tap the Menu key. Tap Settings. Tap Call settings. Tap Voicemail. Tap Voicemail again. View the voicemail number. Press and hold the 1 on your device’s dial pad to call and connect to your voicemail. Press the star * key to access the main menu. Press 4 to access the mailbox options. Press 7 to change the language of the voicemail prompts to either Spanish or English.