All calls going straight to voicemail

FIRST: Are there missed calls in Phone/Recents on the phone? If they are not the problem is in the network, because the calls aren’t getting to your phone. Contact your carrier: 

• check with your carrier that they don’t have a local outage, and that you didn’t have any settings that would have immediately invoked voicemail, such as call forwarding.
• check up on them at Down Detector - outages

If they are in Recents here’s what to check:

• Check the MUTE switch on the left side of the phone, above the volume buttons. It should be towards the screen
• Check the volume setting. With the Home screen displayed, press the VOLUME UP button on the left side of the phone. It’s above the VOLUME DOWN button.
• Go to Settings/Phone. There’s a switch for Silence Unknown Callers. If it is on any calls from numbers not in your contacts will go directly to voicemail.
• Also in Settings/Phone: Make sure Call Forwarding is off.
• iOS 14 & older: Go to Settings/Do not Disturb. Turn it off if it is on. Also turn off Scheduled. With both off none of the other switches there matter.
• iOS 15: Go to Settings/Focus, and verify that all focus settings are disabled.
• Go to Settings/Sounds & Haptics. Make sure there is a sound assigned to Ringtone.
• Go to Settings/Accessibility/Touch/Call Audio Routing and make sure Auto-Answer Calls is off.
• Go to Settings/Screen Time/Communications Limits. Tap each of the 2 entries and make sure both are “Everyone"
• Restart your phone-->RESTART your iPhone, iPad, or iPod touch - Apple Support
• If all else fails, talk your carrier into replacing your SIM card (thanks to ASC user DShelbyD)

Hi, cassandra91!

Many other factors would be helpful to know to solve this problem. First of all, try force restarting your iPhone by pressing volume up, pressing volume down, and then holding the power button for about 10 seconds. You can also follow this article: Force restart iPhone. Before I continue, I have a couple of questions.

• What carrier are you using?
• When did this issue start?
• When did you get this phone (estimate)?
• Does your carrier have any call filters?

For example, I personally have experienced this issue on Verizon because there is a call filter that blocks numbers similar to yours. Make sure you check your filters and blocked list, and also have call forwarding turned off if the option is given to you. Another thing I would make sure of is that in Settings-->Phone, Silence Unknown Callers is turned off at least until you can figure out what the issue here is.

Look forward to your response!