After migration from 2013 to 2016, we are facing a weird issue.
While a visitor group member log into portal, they are facing issue with summary link webpart (in all the pages wherever summary i). The webpart throws error "unable to display this web part. to troubleshoot the problem open this web page in a Microsoft SharePoint Foundation - Compatible HTML..."
But, If we once log in with admin account (or) user with full control, all the visitor group members will be able to view the webpart. Even if the system account logs out they will be able to view the webpart without any issue. So due to this, every day early morning we are forced to log in with admin account and sign out.
Log File Reference
Entering Monitored Scope (Request (GET:https://insight.company.com/Style%20Library/XSL%20Style%20Sheets/ItemStyle.xsl)). Parent=None e62f2e9f-b87d-50ed-c97e-cbaf84e5b195
Looking up SPSite by ID 872d2fa4-de04-420e-a26e-e14d3748c0e0 in memory. e62f2e9f-b87d-50ed-c97e-cbaf84e5b195
Name=Request (GET:https://insight.company.com/Style%20Library/XSL%20Style%20Sheets/ItemStyle.xsl) 0d302e9f-983b-50ed-c97e-cef24af11193
SPRequestModule.BeginRequestHandler End 0d302e9f-983b-50ed-c97e-cef24af11193
Web Content Management Publishing aytib ObjectCachePerRequest Global:True, Enabled:False 0d302e9f-983b-50ed-c97e-cef24af11193
SPRequestModule.PostAuthenticateRequestHandler Begin 0d302e9f-983b-50ed-c97e-cef24af11193
Authentication Authorization agb9s Non-OAuth request. IsAuthenticated=False, UserIdentityName=, ClaimsCount=0 0d302e9f-983b-50ed-c97e-cef24af11193
Runtime ajd6k Value for isAnonymousAllowed is : False 0d302e9f-983b-50ed-c97e-cef24af11193
Runtime ajd6l Value for checkAuthenticationCookie is : True 0d302e9f-983b-50ed-c97e-cef24af11193
Claims Authentication af32k Claims Windows Sign-In: Sending 401 for request 'https://insight.company.com/Style Library/XSL Style Sheets/ItemStyle.xsl' because the user is not authenticated and resource requires authentication. 0d302e9f-983b-50ed-c97e-cef24af11193
Sending HTTP response 401 - text/plain:401 UNAUTHORIZED. 0d302e9f-983b-50ed-c97e-cef24af11193
SPRequestModule.PostLogRequestHandler Begin 0d302e9f-983b-50ed-c97e-cef24af11193
SPRequestModule.PostLogRequestHandler End 0d302e9f-983b-50ed-c97e-cef24af11193
SPRequestModule.EndRequestHandler Begin 0d302e9f-983b-50ed-c97e-cef24af11193
Looking up SPSite by ID 872d2fa4-de04-420e-a26e-e14d3748c0e0 in memory. 0d302e9f-983b-50ed-c97e-cef24af11193
SPRequestModule.PreSendRequestHeaders End 0d302e9f-983b-50ed-c97e-cef24af11193
Micro Trace Tags: 0 avwhy,0 nasq,0 az4z8,0 avwhz,0 aytib,0 avwh6,0 agb9s,0 ajd6k,0 ajd6l,0 af32k,0 b6p2,0 avwia,0 avwib,0 avwic,0 az4z8,0 avwh5 0d302e9f-983b-50ed-c97e-cef24af11193
Sending HTTP response 302 for HTTP request GET to https://insight.company.com/Style%20Library/XSL%20Style%20Sheets/ItemStyle.xsl 0d302e9f-983b-50ed-c97e-cef24af11193
Could not get SPWeb so could not get user key. 0d302e9f-983b-50ed-c97e-cef24af11193
No user key for user in request usage. 0d302e9f-983b-50ed-c97e-cef24af11193
Leaving Monitored Scope: (Request (GET:https://insight.company.com/Style%20Library/XSL%20Style%20Sheets/ItemStyle.xsl)) Execution Time=2.42444456472394; CPU Milliseconds=2; SQL Query Count=0; Parent=None 0d302e9f-983b-50ed-c97e-cef24af11193
SPRequestModule.EndRequestHandler End 0d302e9f-983b-50ed-c97e-cef24af11193
Sending HTTP response 401 - text/plain:401 UNAUTHORIZED. 0d302e9f-983b-50ed-c97e-cef24af11193
SPApplicationAuthenticationModule.IsBearerChallengeRequested: Return 'False'. 0d302e9f-983b-50ed-c97e-cef24af11193
Web Parts 89a1 High Error while executing web part: System.Xml.Xsl.XslLoadException: XSLT compile error. An error occurred at (1,462). ---> System.Net.WebException: The remote server returned an error: (401) Unauthorized. at System.Net.HttpWebRequest.GetResponse() at System.Xml.XmlDownloadManager.GetNonFileStream(Uri uri, ICredentials credentials, IWebProxy proxy, RequestCachePolicy cachePolicy) at System.Xml.XmlUrlResolver.GetEntity(Uri absoluteUri, String role, Type ofObjectToReturn) at Microsoft.SharePoint.WebPartPages.WSSXmlUrlResolver.GetEntity(Uri absoluteUri, String role, Type ofObjectToReturn) at System.Xml.Xsl.Xslt.XsltLoader.CreateReader(Uri uri, XmlResolver xmlResolver) at System.Xml.Xsl.Xslt.XsltLoader.LoadStylesheet(Uri uri, Boolean include) at System.Xml.Xsl.Xslt.XsltLoader.LoadStylesheet(XmlReader reader, Boolean include) --- End of inner exception stack trace --- at System.Xml.Xsl.Xslt.XsltLoader.LoadStylesheet(XmlReader reader, Boolean include) at S ystem.Xml.Xsl.Xslt.XsltLoader.Load(Compiler compiler, Object stylesheet, XmlResolver xmlResolver) at System.Xml.Xsl.Xslt.Compiler.Compile(Object stylesheet, XmlResolver xmlResolver, QilExpression& qil) at System.Xml.Xsl.XslCompiledTransform.LoadInternal(Object stylesheet, XsltSettings settings, XmlResolver stylesheetResolver) at Microsoft.SharePoint.WebPartPages.DataFormWebPart.LoadXslCompiledTransform(WSSXmlUrlResolver someXmlResolver) at Microsoft.SharePoint.WebPartPages.DataFormWebPart.GetXslCompiledTransform() at Microsoft.SharePoint.WebPartPages.DataFormWebPart.PrepareAndPerformTransform(Boolean bDeferExecuteTransform) 0d302e9f-581c-50ed-c97e-cad34f734763
Web Parts 89a2 High InnerException 1: System.Net.WebException: The remote server returned an error: (401) Unauthorized. at System.Net.HttpWebRequest.GetResponse() at System.Xml.XmlDownloadManager.GetNonFileStream(Uri uri, ICredentials credentials, IWebProxy proxy, RequestCachePolicy cachePolicy) at System.Xml.XmlUrlResolver.GetEntity(Uri absoluteUri, String role, Type ofObjectToReturn) at Microsoft.SharePoint.WebPartPages.WSSXmlUrlResolver.GetEntity(Uri absoluteUri, String role, Type ofObjectToReturn) at System.Xml.Xsl.Xslt.XsltLoader.CreateReader(Uri uri, XmlResolver xmlResolver) at System.Xml.Xsl.Xslt.XsltLoader.LoadStylesheet(Uri uri, Boolean include) at System.Xml.Xsl.Xslt.XsltLoader.LoadStylesheet(XmlReader reader, Boolean include) 0d302e9f-581c-50ed-c97e-cad34f734763
High Leaving Monitored Scope: (DataBinding DataFormWebPart (Quick Links)) Execution Time=269.318634528635; CPU Milliseconds=30; SQL Query Count=11; Parent=Request (GET:https://insight.company.com/Departments/PMO/Pages/default.aspx) 0d302e9f-581c-50ed-c97e-cad34f734763