When using Ring Central app on an android phone, when making and receiving calls, people can not hear me when talking, unless I change it to Speaker phone during the call, then they can hear me fine. If I turn off speaker phone during call, they cannot hear me.

Nothing wrong with phone as normal phone calls and MS Teams calls all work fine when using the phone normally (up to ear) and on speakerphone.

Have checked all the settings and Microphone is added to Ring Central App etc.
Have wiped the phone back to factory settings and update it, and made sure that have the latest RC app from play store. Cannot understand why it works on Speaker and not on normal (up to ear) just for this App????

Any help appreciated.