Why are my invoices going to customers spam folders.

Thanks for joining the Community, @jcullenheating-g 

Email providers may mistakenly identify emails sent from QuickBooks as spam if they are received repeatedly. Customers can mark an email as 'Not spam' and future email invoices should then be received to their inbox. 

If you continue to experience any issue with invoice delivery, please see guide with 3 solutions for when customers aren't receiving your emails.