My colleague's STS site suddenly showed this error when she tried to add New Item.
Unable to display this Web Part. To troubleshoot the problem, open this Web page in a Microsoft SharePoint Foundation-compatible HTML editor such as Microsoft SharePoint Designer. If the problem persists, contact your Web server administrator.
Correlation ID: Some GUID
It has worked until today for a month and I haven't made any change in the source.
I have checked on the internet and found the following solution on this forum: Unable to display this Web Part - using data form web part with grouping and large list
My source looked similar to this, so I changed the
. However the error still came up and couldn't open the New Item.
I have no clue to this error because it suddenly happened. (I am not the one who customised the source.)