Emailing Invoices after Outlook failed to email for whatever reason

SOLVED

With Outlook activated in advance (and remaining in that position at all relevant times) I sent email invoices to my clients beginning with A and everything worked, but when I did the rest of my clients (B-Z), Outlook did not receive any of the emails from Timeslips and the problem with Timeslips/Outlook continues over the years without letup. The problem has plagued me for years and hasn't changed with the 2022 version.

Does anyone know how I can send the B-Z invoices (which are in a single pdf file of hundreds of pages) without emailing each invoice separately?

In other words, can I send the emails in one operation through Outlook after what  I've dome already?