Why my Moto G5 Plus is not ringing many occasions although the signal is ok?

[AC Question]

I purchased Moto G5 Plus in March 2017 through Flipkart. Since last 15 days it is not ringing during incoming calls. Only missed called notices are lest. I use two sims & the signals of both sims are always good. Rebooting, resetting of sims did not produce any result.

 

[anon(123856)]

Try wiping the cache partition. It may or may not help but it's easy to try and you won't lose any data.
Have you tried assigning a different ringtone as a test?
When you assign a ringtone do you hear the sample?