With the appearance of GraphConnector, there are now two connectors in this plugin, and only one can be activated simultaneously. Select the connector in the WEB-INF/param/runtime.xml :
For the classic Exchange on-premise compatible connector :
<org.ametys.plugins.messagingconnector.MessagingConnector>org.ametys.plugins.exchange.ExchangeConnector</org.ametys.plugins.messagingconnector.MessagingConnector>
<org.ametys.plugins.messagingconnector.MessagingConnector>org.ametys.plugins.exchange.ExchangeConnector</org.ametys.plugins.messagingconnector.MessagingConnector>
<org.ametys.plugins.messagingconnector.MessagingConnector>org.ametys.plugins.exchange.ExchangeConnector</org.ametys.plugins.messagingconnector.MessagingConnector>
For the Office 365 compatible connector :
<org.ametys.plugins.messagingconnector.MessagingConnector>org.ametys.plugins.exchange.GraphConnector</org.ametys.plugins.messagingconnector.MessagingConnector>
<org.ametys.plugins.messagingconnector.MessagingConnector>org.ametys.plugins.exchange.GraphConnector</org.ametys.plugins.messagingconnector.MessagingConnector>
<org.ametys.plugins.messagingconnector.MessagingConnector>org.ametys.plugins.exchange.GraphConnector</org.ametys.plugins.messagingconnector.MessagingConnector>