Moto G5 Plus some incoming calls going straight to voicemail

Moto G5 Plus

My Choice + 1GB

1GB data

This is my husband’s phone. He’s had it for a couple of years. In the past month he has had some callers say their call goes straight to his voicemail. The phone does not ring, and there is no notification of a call coming in. Then, the supposed voicemail left by caller is not to be found. This is husband’s work phone. Please help.

We’ve restarted the phone several times.
He’s changed his voicemail message to say “Please leave a text because I’m having trouble with my phone.”

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