Urgent help needed. After upgrading from version 7.4.3 to 7.11.1, I cannot save&Publish. I get this long and tiresome exception:

An error occured
One or more errors occurred.

Exception Details
System.AggregateException: One or more errors occurred.
Stacktrace
at System.Threading.Tasks.Task.ThrowIfExceptional(Boolean includeTaskCanceledExceptions)
   at System.Threading.Tasks.Task.Wait(Int32 millisecondsTimeout, CancellationToken cancellationToken)
   at Umbraco.Web.WebApi.Binders.ContentItemBaseBinder`2.BindModel(HttpActionContext actionContext, ModelBindingContext bindingContext)
   at System.Web.Http.ModelBinding.ModelBinderParameterBinding.ExecuteBindingAsync(ModelMetadataProvider metadataProvider, HttpActionContext actionContext, CancellationToken cancellationToken)
   at System.Web.Http.Controllers.HttpActionBinding.<ExecuteBindingAsyncCore>d__0.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Web.Http.Controllers.ActionFilterResult.<ExecuteAsync>d__2.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Web.Http.Filters.AuthorizationFilterAttribute.<ExecuteAuthorizationFilterAsyncCore>d__2.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Web.Http.Filters.AuthorizationFilterAttribute.<ExecuteAuthorizationFilterAsyncCore>d__2.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Web.Http.Filters.AuthorizationFilterAttribute.<ExecuteAuthorizationFilterAsyncCore>d__2.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Web.Http.Filters.AuthorizationFilterAttribute.<ExecuteAuthorizationFilterAsyncCore>d__2.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Web.Http.Controllers.ExceptionFilterResult.<ExecuteAsync>d__0.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Web.Http.Controllers.ExceptionFilterResult.<ExecuteAsync>d__0.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Web.Http.Dispatcher.HttpControllerDispatcher.<SendAsync>d__1.MoveNext()
Inner Exception
System.AggregateException: One or more errors occurred.
at Umbraco.Web.WebApi.Binders.ContentItemBaseBinder`2.<>c__DisplayClass5_0.<BindModel>b__1(Task`1 x)
   at System.Threading.Tasks.Task.Execute()
Inner Exception
AutoMapper.AutoMapperMappingException: 

 Mapping types:
 Property -> ContentPropertyDto
 Umbraco.Core.Models.Property -> Umbraco.Web.Models.ContentEditing.ContentPropertyDto

 Destination path:
 ContentItemDto`1.Properties.Properties.Properties23[23]

 Source value:
 Umbraco.Core.Models.Property
at Umbraco.Web.WebApi.Binders.ContentItemBaseBinder`2.<GetModelAsync>d__7.MoveNext()
Inner Exception
System.NullReferenceException: Object reference not set to an instance of an object.
at SEOChecker.Core.Helpers.ContextHelper.get_Services()
   at SEOChecker.Core.Repository.Definition.DefinitionFactory.Single(String alias)
   at SEOChecker.Core.Config.Configuration.(String , String )
   at SEOChecker.Core.Config.Configuration.GetDocumentTypeByAlias(String alias)
   at SEOChecker.DataTypes.PropertyEditors.PropertyEditorWrappers.RobotsTxtPropertyWrapper.ConvertDbToEditor(Property property, PropertyType propertyType, IDataTypeService dataTypeService)
   at Umbraco.Web.Models.Mapping.ContentPropertyBasicConverter`1.Convert(ResolutionContext context)
   at Umbraco.Web.Models.Mapping.ContentPropertyDtoConverter.Convert(ResolutionContext context)
   at AutoMapper.MappingExpression`2.<>c__DisplayClass23.<ConvertUsing>b__22(ResolutionContext context) in c:\dev\AutoMapper\src\AutoMapper\Internal\MappingExpression.cs:line 469
   at AutoMapper.Mappers.TypeMapMapper.Map(ResolutionContext context, IMappingEngineRunner mapper) in c:\dev\AutoMapper\src\AutoMapper\Mappers\TypeMapMapper.cs:line 22
   at AutoMapper.MappingEngine.AutoMapper.IMappingEngineRunner.Map(ResolutionContext context) in c:\dev\AutoMapper\src\AutoMapper\MappingEngine.cs:line 246

What i've found out:

If I remove SEOChecker version 2.0.1, and install SEOChecker that is < 2.0.0, then it works (though save process is slow).

If I remove SEOChecker completely, It works and it works fast. Since I need SEOChecker, removing it is not really an option, nether downgrading it.

i have a theory that it has something to do with MySql (I Use sql server in my project).

I have this line in my Web.Config:

<siteMap>
  <providers>
    <remove name="MySqlSiteMapProvider" />
  </providers>
</siteMap>

but it does nothing.

I'm in need of dire help. URGENT .

Thanks, Rotem