SmtpClient.send - Could not find a part of the path - smtpclient

Question

I'm trying to write an email to my local folder. I successfully wrote an email to my documents folder using this code:
using (var client = new SmtpClient())
{
client.UseDefaultCredentials = true;
client.DeliveryMethod = SmtpDeliveryMethod.SpecifiedPickupDirectory;
client.PickupDirectoryLocation = tempDocsPath;
client.Send(message);//Writes to the PickupDirectoryLocation
}
However, when I ported this same code to another project, it gives me this error:
System.Net.Mail.SmtpException : Failure sending mail. ---> System.IO.DirectoryNotFoundException : Could not find a part of the path 'C:\Users\josh.bowdish\source\repos\GenerateEmail\GenerateEmail\bin\Debug\net461\tempFiles\AAMkAGUyODNhN2JkLThlZWQtNDE4MS1hODM1LWU0ZDY4Y2NhYmMxOQBGAAAAAABKB1jlHZSIQZSWN7AYZH2SBwDZdOTdKcayQ5NMwcwkNT7UAAAAAAEMAADZdOTdKcayQ5NMwcwkNT7UAACn\0a5b24a5-d625-4ecd-9990-af5654679820.eml'.
I've verified that the directory it's trying to write to exists, even rewrote it to look like this:
private static string WriteEmail(MailMessage message, string messageDirectory)
{
if (Directory.Exists(messageDirectory))
{
using (var client = new SmtpClient())
{
client.UseDefaultCredentials = true;
client.DeliveryMethod = SmtpDeliveryMethod.SpecifiedPickupDirectory;
client.PickupDirectoryLocation = messageDirectory;
client.Send(message);//Writes to the PickupDirectoryLocation
}
...
}
//stuff that returns the full email path
}
It breaks on the client.Send() line with the above error. As far as I can tell the code paths are identical. I've tried writing to the same folder that the other project is working with to no avail. The only thing I can think of is it's trying to write the email file before it exists, but the other project is writing it just fine.
Can someone tell me what is generating this error?
Thanks,
~Josh

Answer 1

This could be a permissions problem. Ensure that the account that your application is running under has permissions to "write" to this directory. Your Directory.Exists could be passing since it is only checking if the directory is there, but failing when trying to actually write to it.