diff --git a/addons/mail/static/src/components/rtc_configuration_menu/rtc_configuration_menu.xml b/addons/mail/static/src/components/rtc_configuration_menu/rtc_configuration_menu.xml
index 5cc1d2b9c5d..4cc42821fd5 100644
--- a/addons/mail/static/src/components/rtc_configuration_menu/rtc_configuration_menu.xml
+++ b/addons/mail/static/src/components/rtc_configuration_menu/rtc_configuration_menu.xml
@@ -9,7 +9,7 @@
                     <div>
                         <select name="inputDevice" class="o_RtcConfigurationMenu_optionDeviceSelect" t-att-value="messaging.userSetting.audioInputDeviceId" t-on-change="_onChangeSelectAudioInput">
                             <option value="">Browser default</option>
-                            <t t-if="state.userDevices" t-foreach="state.userDevices" t-as="device">
+                            <t t-if="state.userDevices" t-foreach="state.userDevices" t-as="device" t-key="device_index">
                                 <t t-if="device.kind === 'audioinput'">
                                     <option t-att-value="device.deviceId"><t t-esc="device.label"/></option>
                                 </t>