I did some changes index.html in sharepoint designer. Although I got the changes back, it happened.
Server Error in '/' Application. Parser Error Description: An error occurred during the parsing of a resource required to service this request. Please review the following specific parse error details and modify your source file appropriately.
Parser Error Message: Duplicate ContentPlaceHolder 'PlaceHolderPageTitle' were found. ContentPlaceHolders require unique IDs.
Line 80: Line 81: Line 82: Line 83: Line 84:
Source File: /_catalogs/masterpage/UMA/index.master Line: 82
Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.7.3163.0