Icomming call goes directly to voicemail. Iphone 6s, Especially when locked

Hello Herman,

Thank you for using Apple Support Communities.

I understand that incoming calls are going straight to voicemail, especially when the iPhone is locked. My first thought is that the Do Not Disturb feature has been turned on. Take a look at this article to check these settings.

Use Do Not Disturb on your iPhone, iPad, or iPod touch

Cheers