Could not save list changes to the server

[Shibu Mathew]

I created a community site and then went on to create a simple list. In the sharepoint designer 2013, I have to build a new custom form for the list created. 

On creating a new custom form of display type, I get a error displaying "Could not save list changes to the server"

I have full control access to the site. Not sure how to resolve this issue.

[#2]

In general I would avoid to use SPD 2013 to customize SharePoint Online sites...might I ask what kind of customization you want to do?