Within MYOB ARL's settings, there are various options on how to email the invoice;
For example there's 2 options on how to send the invoice out of MYOB;
(a)The invoice can be emailed directly from MYOB's mail-server or
(b) it can be sent from MYOB using your Outlook mail-server
But the most important option where Invitbox is concerned, is when using option (a) you have the choice of sending the invoice with just a link in the email (which is useless for sending to Invitbox), or instead you can choose to attach the PDF invoice to the email you're sending (this is what is needed)
To find these settings just log into MYOB & at the very top click on:
SETUP> PREFERENCES> EMAILING tab
and you'll see the settings in the image below.
It you have ticked the box: 'Send Emails Using AccountRight', make sure you select the 'When Emailing Invoices' option to this:
'Include a link to online invoices & include a PDF'>
then click on OK to save.
If you do not have the box ticked, you're using option(b)which means you're sending the invoices from MYOB using your Outlook mail-server and this greys out the options of sending a link and/or an attached PDF [as shown in screenshot below]. Sending this way means your emails should already have a PDF attached - which is what Invitbox needs - so you shouldn't need to change anything.
However if they aren't sending as an attached PDF let us know as we will need to look into it deeper.