After two or three calls the Viber app does start with loudspeakers on (for both incoming and outgoing calls) and there is no way to switch them off in order to talk without all people around hearing my conversation partner. The switch for ‘loudspeaker’ in the Viber menu does not react, and I didn’t find any useful option in the settings. Only solution: uninstall and reinstall Viber. Can somebody give me advice?
Stefan