I am running Umbraco 11.4.0 after a recent upgrade from 7 and have upgraded to the latest SEO Checker as well. Now I get a null ref exception in my prod site when trying to display Umbraco Forms (11.2.0)

This is my stacktrace:

NullReferenceException: Object reference not set to an instance of an object.
    SEOChecker.Common.Helpers.ConfigurationHelper.GetValidationMode(string validationMode)
    SEOChecker.Common.PropertyEditors.PrevValueEditors.SEOCheckerPropertyConfiguration.Map(object source)
    SEOChecker.Common.Helpers.UmbracoDocumentHelper.GetDataTypeConfiguration<T>(int datatypeNodeId)
    SEOChecker.Common.Helpers.UmbracoDocumentHelper.GetSEOCheckerDataTypeConfig(string doctype)
    SEOChecker.Common.Model.Meta.RawMetaData.get_SEOCheckerDataTypeConfig()
    SEOChecker.Common.Model.Meta.RawMetaData.Initialize(string culture, string segment)
    SEOChecker.Common.Model.Meta.RawMetaData.GetMetaData(IUmbracoDocument document, string culture, string segment)
    SEOChecker.Common.Model.Meta.RawMetaData.GetMetaData(Guid id, string culture, string segment, bool preview)
    SEOChecker.Library.PropertyEditorConverters.SEOCheckerMetadataConverter.ConvertSourceToIntermediate(IPublishedElement owner, IPublishedPropertyType propertyType, object source, bool preview)
    Umbraco.Cms.Core.Models.PublishedContent.PublishedPropertyType.ConvertSourceToInter(IPublishedElement owner, object source, bool preview)
    Umbraco.Cms.Infrastructure.PublishedCache.Property.GetInterValue(string culture, string segment)
    Umbraco.Cms.Infrastructure.PublishedCache.Property.GetValue(string culture, string segment)
    Umbraco.Extensions.PublishedPropertyExtension.Value(IPublishedProperty property, IPublishedValueFallback publishedValueFallback, string culture, string segment, Fallback fallback, object defaultValue)
    Umbraco.Forms.Core.Services.PublishedContentPageService.GetPageElements(IPublishedContent content)
    Umbraco.Forms.Core.Services.PublishedContentPageService.GetPageElements()
    Umbraco.Forms.Web.Services.FormRenderingService.PopulatePageElements(HttpContext httpContext)
    Umbraco.Forms.Web.Services.FormRenderingService.GetFormModelAsync(HttpContext httpContext, Guid formId, Nullable<Guid> recordId, string theme)
    Umbraco.Forms.Web.ViewComponents.RenderFormViewComponent.InvokeAsync(Guid formId, Nullable<Guid> recordId, string theme, bool includeScripts)
    Microsoft.AspNetCore.Mvc.ViewComponents.DefaultViewComponentInvoker.InvokeAsyncCore(ObjectMethodExecutor executor, object component, ViewComponentContext context)
    Microsoft.AspNetCore.Mvc.ViewComponents.DefaultViewComponentInvoker.InvokeAsync(ViewComponentContext context)
    Microsoft.AspNetCore.Mvc.ViewComponents.DefaultViewComponentInvoker.InvokeAsync(ViewComponentContext context)
    Microsoft.AspNetCore.Mvc.ViewComponents.DefaultViewComponentHelper.InvokeCoreAsync(ViewComponentDescriptor descriptor, object arguments)
    AspNetCore.Views_MacroPartials_InsertUmbracoFormWithTheme.ExecuteAsync() in InsertUmbracoFormWithTheme.cshtml
    +
        @(await Component.InvokeAsync("RenderForm",new { formId = form, recordId = recordGuid, theme = theme, includeScripts = includeScripts }))

I also get an exception when trying to open the SEO top menu in backoffice.

System.NullReferenceException, System.Private.CoreLib, Version=7.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e: Object reference not set to an instance of an object.
        at SEOChecker.Common.Trees.SEOCheckerTreeController.GetMenuForNode(String id, FormCollection queryStrings)
       at Umbraco.Cms.Web.BackOffice.Trees.TreeControllerBase.GetMenuForNodeAsync(String id, FormCollection queryStrings)
       at Umbraco.Cms.Web.BackOffice.Trees.TreeControllerBase.GetMenu(String id, FormCollection queryStrings)
       at lambda_method24535(Closure, Object)
       at Microsoft.AspNetCore.Mvc.Infrastructure.ActionMethodExecutor.AwaitableObjectResultExecutor.Execute(ActionContext actionContext, IActionResultTypeMapper mapper, ObjectMethodExecutor executor, Object controller, Object[] arguments)
       at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.<InvokeActionMethodAsync>g__Awaited|12_0(ControllerActionInvoker invoker, ValueTask`1 actionResultValueTask)
       at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.<InvokeNextActionFilterAsync>g__Awaited|10_0(ControllerActionInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)
       at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Rethrow(ActionExecutedContextSealed context)
       at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)
       at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.InvokeInnerFilterAsync()
    --- End of stack trace from previous location ---
       at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeNextExceptionFilterAsync>g__Awaited|26_0(ResourceInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)

Any ideas? Thanks, Josef