Caused by: java.lang.NullPointerException: Cannot invoke "java.time.ZonedDateTime.format(java.time.format.DateTimeFormatter)" because "zonedDateTime" is null
	at org.ametys.core.util.DateUtils.zonedDateTimeToString(DateUtils.java:406)
	at org.ametys.plugins.workspaces.project.helper.MailXSLTHelper.getCalendarEventRepeatUntil(MailXSLTHelper.java:190)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:568)