First ensure that you have setup call recording according to the instructions given here. If you have followed all the steps and you are still not able to see call recordings, there are one or two things you can try.

1. Avoid using Bluetooth headsets

2. Ensure that Truecaller is not the default calling app on your phone.

3. Disable WiFi calling on your phone.

Bluetooth Headsets

Most phones and apps do not record properly when you use a Bluetooth headset. So you may want to switch over to a wired headset before you proceed further.

Truecaller

If you have Truecaller installed on your phone, you have to ensure that it is NOT the default application for calling. 

How do you find out if Truecaller is the default calling application on your phone?

If Truecaller is the default calling application, you will see the following screen whenever you make or receive a call. Note the name 'truecaller' on the top of the screen.

To learn how to remove Truecaller as your default dialer, search google for

"how to remove truecaller as a default dialer in <phone model>"

where you must replace <phone model> with the actual model of the phone you use. For example, if you use a Redmi Note 8, search google for 

"how to remove truecaller as a default dialer in Redmi Note8" 

You will find plenty of tutorials online on how to remove Truecaller as the default dialer your phone.

Wi-Fi calling

Most phones and apps do not record properly when you Wi-Fi calling is enabled.

To learn how to remove disable Wi-Fi calling, search google for

"how to disable wifi calling in <phone model>"

where you must replace <phone model> with the actual model of the phone you use. For example, if you use a Redmi Note 8, search google for 

"how to disable wifi calling in Redmi Note8" 

You will find plenty of tutorials online on how to disable Wi-Fi your phone.