Thank you for your prompt response.
Yes I’m using the system email and I’ve tried changing the invoice status, that didn’t work.
I used the FluentSMTP plugin to get the email logs and it shows that the emails were sent even though they are never received by the contact email.
Using FluentSMTP I tested google smtp and my webmail smtp and those managed to get the invoices delivered to the contact email. I will try Jetpack CRM SMTP mail delivery method instead of FluentSMTP so that can be one less plugin being used.
Although I’ve managed to get smtp working with invoices I’d still like to get to the bottom of the initial issue before upgrading Jetpack CRM.
I will get the error logs and email logs and send them later in the day via the bug report form