We discovered this problem some time ago.

We always follow up and check with clients if they receive it which is annoying.

Is there any option how to check that clients received it other than portal way?

Not all clients wants to set up portal as some clients are one off.

And how to persuade them to set up portal anyway?

If there is option that clients receive link with invoice or estimate as other accounting providers, then once client click on it, we will know they received it.

Let me know if you planning this sort of option in near future as we need to make our system easier.

Also we reached 500 clients and before we upgrade, we need to be sure this Not Receiving is sorted otherwise we need to look elsewhere for Invoicing system.

Thank you for your help