Problem setting up voicemail

It's easy and you can follow below steps.

you can set up Voicemail and then record voicemail message by following these steps:

1. Tap on Phone > Voicemail;
2. Usually, you will be guided to automated voicemail system and you can simply follow voice prompt to set up Voicemail. If not, you have to follow these steps:
a. Click "Set Up Now". You will be required to enter password. Tap password and then click "Done". Re-tap again and click "Done". Please keep in mind that password should be between 4-6 digits in length.
b. Click "Custom" to record voicemail. Activate "Record" to start recording and tap "Stop" to finish recording voicemail. After you finish recording voicemail, tap on "Save".

For more details, check: How to Record a Voicemail on iPhone

According to iPhone faq.org: " How can set the number of rings on my iPhone before voicemail picks up?
You can set the iPhone to wait longer or shorter than the default 20 seconds before it goes to voicemail when receiving an incoming call. This will result in a different number of rings before the voice messaging system picks up the line and plays your outgoing message. To change the amount of time the iPhone will ring follow these steps:
1. Open the phone app and dial *#61# on the Keypad. Press the Call button.
2. Locate this text on the screen: "Setting Interrogation Succeeded, Voice Call Forwarding, When Unanswered, Forwards to +" and record the 11-digit number after the + symbol.
3. Touch the Dismiss button. Now enter this code on the Keypad: *61*+ followed by the 11-digit Forwards to number recorded in step 2, followed by *11 and *ringtime#. Ringtime is the number of seconds you want your iPhone to ring before voicemail picks up. Your finished code should look something like this:
*61*+18555513466*11*30#
In the example above the ring time is set to 30 seconds. Press the Call button.
4. You should receive the message: Setting Activation Succeeded. Press Dismiss and next time you receive a call it will ring for the new amount of time before going to voicemail."
According to Apple Tool Box.com: "having this problem, please try the followings:

• Make sure that iPhone's Ring/Silent switch is OFF meaning ringer is ON. A bell will flash briefly on the screen when you turn on the ringer.
• Make sure that the Do Not Disturb setting is not silencing calls (Settings > Do Not Disturb).
• Make sure that Airplane Mode is OFF (Settings > Airplane Mode).
• Make sure that your carrier software is up to date (Settings > General > About)."
  
  AccorA

It's simple. Just follow below steps.

To record voicemail on iPhone, you have to first set up Voicemail and then record voicemail message by following these steps:

1. Tap on Phone > Voicemail;
2. Usually, you will be guided to automated voicemail system and you can simply follow voice prompt to set up Voicemail. If not, you have to follow these steps:
a. Click "Set Up Now". You will be required to enter password. Tap password and then click "Done". Re-tap again and click "Done". Please keep in mind that password should be between 4-6 digits in length.
b. Click "Custom" to record voicemail. Activate "Record" to start recording and tap "Stop" to finish recording voicemail. After you finish recording voicemail, tap on "Save".



For more details, check: How to Record a Voicemail on iPhone

You have to do it when you call your voicemail to check messages, its in the system setting from your cell carrier AT&T

Adding Voicemail for the First Time

1. Tap the "Phone" button on your iPhone.
2. Select "Voicemail." The iPhone will prompt you to create a password for accessing your voicemail, then will allow you to record your first greeting.
3. Click "Save" to set your recording to your voicemail greeting
   

Recording a New Greeting

1. Tap the "Phone" button on your iPhone.
   
2. Select "Voicemail."
   
3. Choose "Greeting > Custom."
4. Select "Record" and begin recording your voicemail greeting.
5. Hit "Save" to set your recording to your new voicemail greeting

Hi, have you tried to 
- reboot the phone - connect the iphone and synchronize it to your mac - do an update?

call 611 from the phone you can press I think option 1 then option 3 you should be able to reset your voicemail pwd. however before you do that you should call your phone from another phone not just press 1 send. by calling your phone it will let you know if you have a voicemail box actually setup porperly.

Had the same problemwith my iPhone 3G this is how I fixed it -

1) From the iPhone 3G, I called my own iPhone 3G number.
2) Went through the setup. After finishing the ssetup Hang off the iPhone 3G.
3) Then the voicemail button on the iPhone 3G worked - first time, there was a **** pause, it asked me to enter my voicemail password that I had set in step 2, and that's it.

Good luck.

go to''brightness'' setting