WP Mail SMTP – testmail – sendinblue – cURL error 60

Replies: 0

Versions:
WordPress: 5.7.2
WordPress MS: No
PHP: 7.4.13
WP Mail SMTP: 2.8.0

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

Debug:
Mailer: Sendinblue
[0] cURL error 60: SSL certificate problem: unable to get local issuer certificate (see https://curl.haxx.se/libcurl/c/libcurl-errors.html)

Any Ideas what to change or fix?
Thx
Wolfgang