Test send in Marketing Cloud does not send email

Question

I have this block of AMPScript written in my template.

/*AMPSCRIPT BLOCK BEGIN */
    %%[
    var @topupParam, @topupfilename
    
    set @topupParam = "\AccountActivity\022023\110697.pdf"
    set @topupfilename = "a.pdf"
    
    AttachFile("FTP", @topupParam, @topupfilename)
    
    ]%%
/* AMPSCRIPT BLOCK END */
    
    Dear %%First Name%%
    <br><br>
    Please find attached your latest <b>Monthly Activity Statement</b> showing the services we have provided to you.
    <br>
    
    <p>
     Please also find your tax invoice attached. 
    </p>
    
    
    <p>
      If you have any questions, please contact us and we will be happy to help.
    </p>
     
    <br>

As can be seen, for every contact in our data extension we attach the same file to our email For some reason, test send does not work.

"Test send" does not error during "Preview" but simply does not send any email.

Please see the image below where it says 0 emails sent.

Key points

1.I just created this FTP folder (AccountActivity) and its subfolder (022023) now. Is there a delay after a folder is created in FTP for it to be recognised by AMPscript ?

2.To further analyze the problem I even removed the entire AMPscript block and just ran a test email with the following template, even then when I did a test I did not get any email.

3.We already have bought the AMPscript attachfile feature and have been able to test attachments to our customers earlier.

4.This is a sendable data extension with only one record for our testing purpose

Can someone please provide their inputs or ideas ?

UPDATE :

If I just process the Data Extension in Journey Builder, I get "Errored" which I believe to be an improvement as shown below

Is there any way to check what that error is ? Any logging or anything ?

Answer 1

A few things to check, which could help you.

1. Making sure your subscribe is Active in 'All Subscribers'.
2. Are you using a template based email, which has any ampscript blocks called or referenced to? Generally, an error indicates ampscript error.There might be some nested ampscript blocks.
3. Can you create a blank html email, with only the necessary things and then try and send?
4. Can you take your First Name as a ampscript value, such as ,

set @firstName = AttributeValue("First Name") and then showing as Dear %%=v(@firstName)=%%.

Answer 2

Pretty sure that files must exist at the root of the Import folder for the AttachFile() function to work.

Official docs are here.

Update

I'd suggest reviewing the NotSent tracking data. The Reason value will indicate the issue -- including ListDetective suppressions.