Issues when using the HTML formatter

[BartNSTCL]

Using Serilog.Sinks.Email v4.0

I setup a simple test and With the HTML formatter, I'm not getting the Exception info.
When I have Body commented out, I get the email I expect:

2025-02-18 07:51:27.419 -06:00 [Error] Hotmill_Background_Services - CoilJsonServices - Error: On CoilID:"Test" System.DivideByZeroException: Attempted to divide by zero. at Hotmill_Background_Services.Services.CoilJsonService.UpdateCoilJson() in C:\Users\bart.lynn\source\repos\HotMill\Stand Alone Programs\Hotmill_Background_Services\Hotmill_Background_Services\Services\CoilJsonService.cs:line 119

When I have the Body set as : Body = new MyHtmlBodyFormatter(), I get this:
Hotmill_Background_Services - CoilJsonServices - Error: On CoilID:"Test"

Its like the line logEvent.RenderMessage(buffer); is not loading the Exception data. I checked, and its there:

Not sure what I have setup wrong.

In the main code I have:
using var logEmail = new LoggerConfiguration()
.WriteTo.Email(
options: new()
{
From = REDACTED,
To = [REDACTED],
Host = REDACTED,
Subject = new MessageTemplateTextFormatter("Log Messages - Hotmill_Background_Services"),
Body = new MyHtmlBodyFormatter(),
IsBodyHtml = true,
},
batchingOptions: new()
{
BatchSizeLimit = 10,
BufferingTimeLimit = TimeSpan.FromSeconds(30),
}, restrictedToMinimumLevel: Serilog.Events.LogEventLevel.Error)
.CreateLogger();
var coil = "Test";

logEmail.Error(ex, "Hotmill_Background_Services - CoilJsonServices - Error: On CoilID:{CoilId}", coil);

And the class MyHtmlBodyFormatter (from the ReadMe):

class MyHtmlBodyFormatter : IBatchTextFormatter
{
public void FormatBatch(IEnumerable logEvents, TextWriter output)
{
output.Write("

");
foreach (var logEvent in logEvents)
{
output.Write("");
Format(logEvent, output);
output.Write("");
}

    output.Write("</table>");
}

public void Format(LogEvent logEvent, TextWriter output)
{
    using var buffer = new StringWriter();
    logEvent.RenderMessage(buffer);
    output.Write(WebUtility.HtmlEncode(buffer.ToString()));
}

}