How to stop customer portal invitation

[RG]

Dear Experts,

While working on tickets, if an agent adds a new participant who doesn't have access to JIRA or the customer portal, they receive an invitation to join the Customer portal. We want to disable this invitation for new customers.

Already we have updated Project Settings -> Customer Notifications -> Account Verification Email (Enabled) still users getting invitation.

Account verification email

If enabled, account verification emails will not be sent to new customers. Customers won’t need to verify their email address or set up their account.

Do not send account verification emails