Calendar Form fields are missing and Form Settings is showing: InfoPath does not support customizing the form used for this list.

Question

Created a out of office calendar for the team with a few different filters (type of absence...vacation, training, etc)/views for color indication which was working fine for months.

Since a week ago, it looks like upon clicking into the calendar, the form which pops up no longer has categories to choose the type of leave from, and trying to access the Form Settings section shows: InfoPath does not support customizing the form used for this list.

Is there a fix for this somehow?

Recreating the entire calendar would take ages, as there's multiple people's entries in there, and creating multiple views and colored filters is not a simple task in SharePoint.

Answer 1

This forum handles requests related to Open Specifications documentation issues. 
The Open Specifications can be found at: http://msdn.microsoft.com/en-us/library/cc203350.aspx. 
Your question does not appear to be related to the Open Specifications documentation set. 
     
I suggest you try the following to get assistance.

https://docs.microsoft.com/en-us/answers/topics/office-sharepoint-online.html

Mike Bowen

Escalation Engineer Microsoft Open Specifications