A common scenario we find is that some patients aren't receiving emails from practitioners relating to their invoice. One way to check if an invoice is sent is to see if it is visible under Patients -> Select the Patient record -> Select the Messages tab, if it is visible then it has been sent.
We can only track email receipts as far as the patient's mail server (ie. gmail, outlook, hotmail etc). From time to time you may receive dashboard notifications about email failures. This will happen when the recipient's email server has rejected the email. After delivery, the recipient's email server may do additional processing. For example: filtering junk email, checking for suspected phishing emails, and sometimes grey listing for first time senders. If the recipient's email server drops email during this process we will not get notified.
Invoice emails are particularly prone to being considered spam or phishing as they are often quite short, generally have a suspicious looking subject, and contain a link.
One good way to improve deliverability is to increase the text to link ratio. If you do wish to change your email templates so you don't have to re-type everything in over and over again, you can change the templates under "Invoice settings" in Business Setup then scroll to "email body" and edit from there. This will be a default invoice template for all patients.
If you host your own domain, another way to dramatically improve deliverability is by using an SPF record. You can click here if you would like to consider using an SPF record.
You can do this yourself, however it is preferable that your web host set this up for you. The support team is also able to set this up for you if the need arises, please feel free to contact support on firstname.lastname@example.org and ask for further details on the team setting up an SPF record on your behalf.