I just installed Umbraco Forms v8.4.0 (via nuget) into an Umbraco CMS v8.5.3 project (with SQL Server). I have added references to jQuery validate v1.19.1 and jQuery unobtrusive validate (it doesn't seem to have a version) and I have followed the directions on this page ... https://our.umbraco.com/documentation/Add-ons/UmbracoForms/Developer/Rendering-Scripts/ ... since my javascript files are referenced outside the HTML HEAD section.

I create a form with just one field and embedded it into a template using:

Umbraco.RenderMacro("renderUmbracoForm", new { FormGuid = "db967296-c296-493b-8da9-7e3cf2f0b090", ExcludedScripts = "1" })

When I submit the form I get the following error: Unable to cast object of type 'Umbraco.Core.Persistence.FaultHandling.RetryDbConnection' to type 'System.Data.SqlClient.SqlConnection'.

Here's the stack trace:

[InvalidCastException: Unable to cast object of type 'Umbraco.Core.Persistence.FaultHandling.RetryDbConnection' to type 'System.Data.SqlClient.SqlConnection'.]
   NPoco.<>c.<.cctor>b__7_0(DbConnection dbConn) +27
   NPoco.SqlBulkCopyHelper.BulkInsert(IDatabase db, IEnumerable`1 list, SqlBulkCopyOptions sqlBulkCopyOptions) +76
   NPoco.SqlBulkCopyHelper.BulkInsert(IDatabase db, IEnumerable`1 list) +55
   NPoco.DatabaseTypes.SqlServerDatabaseType.InsertBulk(IDatabase db, IEnumerable`1 pocos) +49
   NPoco.Database.InsertBulk(IEnumerable`1 pocos) +135
   Umbraco.Forms.Core.Data.Storage.RecordFieldStorage.InsertRecordFields(IEnumerable`1 recordFields) +675
   Umbraco.Forms.Core.Data.Storage.RecordStorage.InsertRecord(Record record, Form form) +1564
   Umbraco.Forms.Core.Services.RecordService.StoreRecord(Record record, Form form) +1087
   Umbraco.Forms.Core.Services.RecordService.Approve(Record record, Form form) +426
   Umbraco.Forms.Core.Services.RecordService.Submit(Record record, Form form) +1068
   Umbraco.Forms.Web.Controllers.UmbracoFormsController.SubmitForm(Form form, FormViewModel model, Dictionary`2 state, ControllerContext context) +2464
   Umbraco.Forms.Web.Controllers.UmbracoFormsController.GoForward(Form form, FormViewModel model, Dictionary`2 state) +216
   Umbraco.Forms.Web.Controllers.UmbracoFormsController.HandleForm(FormViewModel model) +1085
   lambda_method(Closure , ControllerBase , Object[] ) +103
   System.Web.Mvc.ActionMethodDispatcher.Execute(ControllerBase controller, Object[] parameters) +14
   System.Web.Mvc.ReflectedActionDescriptor.Execute(ControllerContext controllerContext, IDictionary`2 parameters) +157
   System.Web.Mvc.ControllerActionInvoker.InvokeActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary`2 parameters) +27
   System.Web.Mvc.Async.<>c.<BeginInvokeSynchronousActionMethod>b__9_0(IAsyncResult asyncResult, ActionInvocation innerInvokeState) +22
   System.Web.Mvc.Async.WrappedAsyncResult`2.CallEndDelegate(IAsyncResult asyncResult) +29
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +49
   System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethod(IAsyncResult asyncResult) +32
   System.Web.Mvc.Async.<>c__DisplayClass11_0.<InvokeActionMethodFilterAsynchronouslyRecursive>b__0() +58
   System.Web.Mvc.Async.<>c__DisplayClass11_2.<InvokeActionMethodFilterAsynchronouslyRecursive>b__2() +228
   System.Web.Mvc.Async.<>c__DisplayClass11_2.<InvokeActionMethodFilterAsynchronouslyRecursive>b__2() +228
   System.Web.Mvc.Async.<>c__DisplayClass11_2.<InvokeActionMethodFilterAsynchronouslyRecursive>b__2() +228
   System.Web.Mvc.Async.<>c__DisplayClass11_2.<InvokeActionMethodFilterAsynchronouslyRecursive>b__2() +228
   System.Web.Mvc.Async.<>c__DisplayClass7_0.<BeginInvokeActionMethodWithFilters>b__1(IAsyncResult asyncResult) +10
   System.Web.Mvc.Async.WrappedAsyncResult`1.CallEndDelegate(IAsyncResult asyncResult) +10
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +49
   System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethodWithFilters(IAsyncResult asyncResult) +34
   System.Web.Mvc.Async.<>c__DisplayClass3_6.<BeginInvokeAction>b__4() +35
   System.Web.Mvc.Async.<>c__DisplayClass3_1.<BeginInvokeAction>b__1(IAsyncResult asyncResult) +100
   System.Web.Mvc.Async.WrappedAsyncResult`1.CallEndDelegate(IAsyncResult asyncResult) +10
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +49
   System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeAction(IAsyncResult asyncResult) +27
   System.Web.Mvc.<>c.<BeginExecuteCore>b__152_1(IAsyncResult asyncResult, ExecuteCoreState innerState) +11
   System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +29
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +49
   System.Web.Mvc.Controller.EndExecuteCore(IAsyncResult asyncResult) +45
   System.Web.Mvc.<>c.<BeginExecute>b__151_2(IAsyncResult asyncResult, Controller controller) +13
   System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +22
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +49
   System.Web.Mvc.Controller.EndExecute(IAsyncResult asyncResult) +26
   System.Web.Mvc.Controller.System.Web.Mvc.Async.IAsyncController.EndExecute(IAsyncResult asyncResult) +10
   System.Web.Mvc.<>c.<BeginProcessRequest>b__20_1(IAsyncResult asyncResult, ProcessRequestState innerState) +28
   System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +29
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +49
   System.Web.Mvc.MvcHandler.EndProcessRequest(IAsyncResult asyncResult) +28
   System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.EndProcessRequest(IAsyncResult result) +9
   System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +576
   System.Web.HttpApplication.ExecuteStepImpl(IExecutionStep step) +132
   System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +163

What am I missing? I've been over this 10 times and I can't see what I'm doing wrong. I google this error and I find very little so apparently I'm the only one having this issue.

Can anyone help??

Thanks