Error after asking for alternative MFA

MFA is failing for a user for 2 days now (this we should be able to deal with our selves).
When the user chooses the 'alternative' option, we'd expect the user to receive an e-mail however, we notices the server sends out a e-mail (see below).

Any ideas how to deal with this? I unsure as to why en_US would be an invalid culture.

Thanks.

=========================================
The following error
was received by xxv redacted xxx
at 4-8-2022 07:58:53

Error:

CultureNotFoundException
- Culture is not supported. Parameter name: name en_US is an invalid culture
identifier. at System.Globalization.CultureInfo..ctor(String name, Boolean
useUserOverride) at
Devolutions.Server.EmailManager.SendTwoFactorValidationCode(String twoFactorValidationCode,
String specificEmail, String language) at
Devolutions.Server.Controllers.APIControllers.V2.BackendApiController.GenerateAndSendAlternateEmailValidationCode()
at lambda_method(Closure , Object , Object[] ) at System.Web.Http.Controllers.ReflectedHttpActionDescriptor.ActionExecutor.<>c__DisplayClass6_2.b__2(Object
instance, Object[] methodParameters) at
System.Web.Http.Controllers.ReflectedHttpActionDescriptor.ExecuteAsync(HttpControllerContext
controllerContext, IDictionary`2 arguments, CancellationToken
cancellationToken) --- 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.ApiControllerActionInvoker.d__1.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.ActionFilterAttribute.d__6.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at
System.Web.Http.Filters.ActionFilterAttribute.d__6.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.ActionFilterAttribute.d__5.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.d__5.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.d__3.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.d__3.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.d__6.MoveNext()
--- Default





Source:

mscorlib