tl:dr — Watch out for emails from Google regarding your own sign-in activity, as these security emails contain a button that if clicked, will delete all of your App Passwords that allow your consignment/resale software to send email.
tl;dr — As of May 30, 2022, Google no longer supports the Less Secure Apps feature that allowed third party programs (e.g. consignment software such as Peeps’ Software) to be able to send emails. This means, your consignment software likely will no longer be able to send emails from your Gmail account. Going forward, the already-available App Passwords feature in Gmail has to be utilized for sending emails.
ConsignPro and Liberty are incompatible with Gmail or any secure email service.
Consignment stores, are you looking for a way to let your consignors book a consignment appointment online? Google recently added an Appointments feature to Google Calendar.