HI
I just upgraded Davx today from Fdroid today and I started getting the error in the title. I have been using this for a long time without any issues. I did not add any new task for a while, I also did not do any system upgrade relating to Nextcloud. I am not sure what the issue is 
I am using it on LIneage os 7.1.2, Davx 2.4 beta2. My server is Nextcloud v15 running on Debian
See the log please
Hello,
Can you post the (anonymized) contents of this task? https://URL.URL.org/NEXTC/remote.php/caldav/calendars/USER/default-calendar/Nextcloud-6RL263BJL6RY2T5YQ7JSHS.ics
It seems that there’s an UTC property, most probably DTSTAMP, with a timezone (which is not allowed):
Caused by: java.lang.UnsupportedOperationException: Cannot set timezone for UTC properties
See https://forums.bitfire.at/post/10424
Is this the cause? Where does this task come from?
Hi
Thanks for the reply.
I will go through the cal and remove the personal information. Then post is here.
I searched for DTSTAMP and there is one. Let me know if this portion is enough, if not I will post the whole thing later.
BEGIN:DAYLIGHT
TZNAME:CDT
DTSTART:20360309T020000
TZOFFSETFROM:-0600
TZOFFSETTO:-0500
END:DAYLIGHT
BEGIN:DAYLIGHT
TZNAME:CDT
DTSTART:20370308T020000
TZOFFSETFROM:-0600
TZOFFSETTO:-0500
END:DAYLIGHT
END:VTIMEZONE
BEGIN:VTODO
DTSTAMP:20150603T041115Z
UID:20150603T041115Z-18957@4e6efab67458f3d4
CREATED:20150603T041031Z
LAST-MODIFIED:20150603T041031Z
SUMMARY:xxxxx
STATUS:NEEDS-ACTION
PERCENT-COMPLETE:100
COMPLETED;TZID=America/Chicago:20150715T230629
END:VTODO
END:VCALENDAR
Like I mentioned, this was wrking fine, infact that task seems to be created long time ago, and I never got an error about it before.
@tartarian said in Received invalid task from server:
COMPLETED;TZID=America/Chicago:20150715T230629
https://tools.ietf.org/html/rfc5545#section-3.8.2.1 says:
The property can be specified in a “VTODO” calendar component. The value MUST be specified as a date with UTC time.
So fixing the property (change to yyyymmddThhmmssZ) should fix the problem.
Like I mentioned, this was wrking fine, infact that task seems to be created long time ago, and I never got an error about it before.
For tasks, unfortunately DAVx⁵ can’t use the “past event time limit”, because some big servers then don’t report any tasks at all. So all tasks will be synchronized all the time.
Since DAVx⁵ 2.3, invalid tasks are shown to users. Probably you have used DAVx⁵ <2.3 before? Thanks for trying the beta 
Thanks for the follow up. I do not know how to make those changes on the server side really. I just deleted it given that it was entered long time ago. Davx stopped complaining about it.