When a user enters an email address that is not configured as a Portal User, the current experience appears to prompt for a verification code that is never received. This creates the impression that email delivery or the portal is malfunctioning.

Consider displaying a message such as:

"This email address is not an authorized Portal User. Please contact an existing Portal User or your MSP to grant access, or use Guest Checkout."

Many SMBs have invoices forwarded between owners, office managers, bookkeepers, controllers, and AP staff. Most users are unaware that an existing Portal User can add additional users. Providing a clearer message and directing users to the Portal User process would reduce confusion, failed login attempts, and support requests.