Synchronization does not work

[BernhardFahr]

First of all: The app is great!
The initial synchronization / assignment works. All contacts, appointments and tasks are synchronized cleanly.
But neither active nor passive synchronization works afterwards. Test appointments created in Exchange are not transferred to Nextcloud (and vice versa).

There is an error message in Nextcloud's log:
{"reqId":"En7cGX81JLj9zvUogRev","level":3,"time":"2024-09-06T10:00:37+02:00","remoteAddr":"","user":"--","app":"integration_ews","method":"","url":"--","message":"Exception thrown: SoapFault","userAgent":"--","version":"29.0.6.2","exception":{"Exception":"SoapFault","Message":"looks like we got no XML document","Code":0,"Trace":[{"file":"/var/www/nextcloud/apps/integration_ews/lib/Service/Remote/RemoteCommonService.php","line":1276,"function":"__call","class":"SoapClient","type":"->"},{"file":"/var/www/nextcloud/apps/integration_ews/lib/Service/HarmonizationService.php","line":481,"function":"connectEvents","class":"OCA\EWS\Service\Remote\RemoteCommonService","type":"->"},{"file":"/var/www/nextcloud/apps/integration_ews/lib/Tasks/HarmonizationThread.php","line":150,"function":"connectEvents","class":"OCA\EWS\Service\HarmonizationService","type":"->"}],"File":"/var/www/nextcloud/apps/integration_ews/lib/Service/Remote/RemoteCommonService.php","Line":1276,"CustomMessage":"Exception thrown: SoapFault"}}

The surroundings:
Nextcloud 29.06
Exchange Server 2019 (on premise)

[surendranr]

Synchronization does not work. Initial synchronization was working, but now suddenly the active or passive are not working.