Customers not receiving order confirmations

Site URL: https://www.onyxhive.com.au

Hey guys,

my business email is info@onyxhive.com.au and I have linked my domain and email from a third party server/company.

I had 2 customers already that ordered and didn't get the confirmation e-mail of their order, but I have received their order on my end fine. Both users use @gmail.com and @outlook.com

I do understand there prob are heaps of ways for my email to be in spam/junk or not even getting it with settings on their end.

I don't do campaigns, I don't spam customers.

Just wondering, is there a way to know if my business email could be counted as spam or junk?

This happens FREQUENTLY. It's important to add email records to your domain name so that "interwebz" doesnt think its junk. Essentially, Squarespace are sending out an email using your email address but mail programs know that it isnt actually YOUR email but rather someone else pretending to be. So putting the correct records in your DNS records should alleviate this. Mind you, for some of my clients, this still doesnt help.