WP MAIL SMTP Set up Errors

Replies: 0

I set up and confirmed all the DNS record changes (confirmed in sendinblue) but when I send a test email I get the following error:

Versions:
WordPress: 6.0
WordPress MS: No
PHP: 7.4.28
WP Mail SMTP: 3.4.0

Params:
Mailer: sendinblue
Constants: No
API Key: Yes

Debug:
Email Source: WP Mail SMTP
Mailer: Sendinblue
unauthorized: Key not found

Please advise how to troubleshoot as this is the only thing keeping me from launching my site!