Noticed yesterday my customers are not receiving my estimate emails.

Hello there, carsonmon42. You can ask your customers to check their junk or spam folders, as the emails might be hidden there.

If they still can't find them, try clearing and re-entering your email address in QuickBooks Online (QBO). Go to Settings > Account and settings > Company, and select Edit (✎) under Contact info. Delete the address from the Company email field, then re-enter it exactly as it is. Be extra careful not to include any hidden spaces or extra characters before or after the email. Select Save, then Done.

Once you have updated your email settings, send yourself a test transaction. If it doesn't arrive, try using an email address with a completely different domain.

If none of these steps resolve the issue, consider asking an IT expert to add the QuickBooks Online mail server hostnames and IP addresses to your outgoing mail server's allow list to prevent estimates from being mistakenly marked as spam.

If you need any further assistance, you can always get back to this thread.