If your phone keeps going straight to voicemail without ringing, it could be due to several reasons. Firstly, your phone may not have enough network connection or may be in an area with poor coverage. Secondly, your phone may be set in the "Do Not Disturb" mode or may have wrongly set the "Airplane mode" on or may have enabled "Silent mode" without realizing it. Another reason could be a technical issue with your phone's software or hardware, which may need to be addressed by contacting your phone's manufacturer or service provider. The best solution is to check your phone's settings and network connection, and if the issue persists, contact your service provider or phone manufacturer for assistance.