After an upgrade my site's working fine, mostly. However on saving an HTML edit, the saving operation succeeds, but I get an "Ah shucks" with this in the log:

2023-08-13 11:12:24,013 ERROR 31.125.19.169 - en-US - /HtmlEdit.aspx?mid=0&pageid=0 - mojoPortal.Web.Global -  Referrer(https://www.mysite.com/HtmlEdit.aspx?mid=0&pageid=0) useragent Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/115.0.0.0 Safari/537.36 Edg/115.0.1901.203 
System.Configuration.ConfigurationErrorsException: Exception has been thrown by the target of an invocation. ---> System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> System.TypeInitializationException: The type initializer for 'WebStore.UI.Helpers.OfferSearchIndexBuilder' threw an exception. ---> System.IO.FileLoadException: Could not load file or assembly 'log4net, Version=1.2.13.0, Culture=neutral, PublicKeyToken=669e0ddf0bb1aa2a' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)
   at WebStore.UI.Helpers.OfferSearchIndexBuilder..cctor()

I'm not using WebStore in my site, in case that's relevant.

I get a similar but less specific error when trying to visit the Index Browser at https://www.mysite.com/Admin/IndexBrowser.aspx

In this case the error is

System.NullReferenceException: Object reference not set to an instance of an object.
   at ASP.admin_indexbrowser_aspx.__DataBinding__control9(Object sender, EventArgs e)

Here's some info about my site:

mojoPortal Version 2.9.0.1 MSSQL

Operating System Microsoft Windows NT 10.0.17763.0

ASP.NET Info 4.0.30319.42000 Running in Full Trust

FeatureSchema Version

blog2.6.2.1

contactform0.0.0.6

eventcalendar1.0.0.0

feed-manager1.0.1.1

forums2.2.0.5

imagegallery0.0.0.8

kdmediaplayer1.0.0.1

linksmodule1.0.0.9

pollfeature-byChristianFredh0.0.0.5

sharedfiles1.1.0.0

superflexi0.0.2.5

surveyfeature1.9.0.0

webstore0.0.7.4

 

Can you suggest how to fix this? Thanks!

Thanks Joe, this has fixed it.