Sometimes after installing the application on mobile devices, due to permission popup and without reading the message users generally select Allow / deny. This will cause that we are not able to select the email / or contacts while sending the email from the email app. To resolve check the following things:
Went to Android Settings, Apps, Gmail. In the App Permissions section, Contacts disabled. Enabled it, closed everything.
And after opened gmail, it was giving me suggestions of emails as I was typing.