From Microsoft Corporation
MC210713, Stay Informed, Published date: Apr 25, 2020
Updated May 5, 2020: Editing existing Forms is now working as expected. If users attempted to edit existing Forms between April 25, 2020 and May 5, 2020, those forms may not work as expected. Please open a support ticket if this is the case.
We’ve identified an issue that affects SharePoint Designer functionality for creating custom Forms within SharePoint Online.
We identified a code issue with an Application Programming Interface (API) associated with creating new Forms through SharePoint Designer that could cause impact to data integrity. We’ve confirmed that no customers have been affected by the code issue; however, through careful analysis we’ve determined that any changes to fix the issue would likely impact other core service components. In order to maintain our data integrity standards we’ve expedited the deprecation of this feature effective as of 3:00 AM UTC on Saturday, April 25, 2020. This change only affects the action of creating new Forms and does not impact the ability to edit previously created Forms. Users who attempt to create new Forms within the Designer will be shown an error message.
After this change was made, users may have received the error: “Could not save the list changes to the server,” when creating new Forms.
Creating Forms using SharePoint Designer is a legacy feature and we recommend users who were leveraging this functionality to now use PowerApps for this purpose. PowerApps is an easy and powerful tool that allows users operating in the SharePoint Online Modern experience to create and edit custom Forms for SharePoint lists and document libraries right from a browser window. PowerApps does not require traditional coding knowledge or any additional app downloads such as InfoPath.
*Note: SharePoint Online Classic users will need to temporarily switch to the Modern experience to access and utilize PowerApps; though, all custom Forms created in PowerApps are accessible by SharePoint Online Classic experience users.Additional information