Some Brevo account requires IPs to be whitelisted to make API calls.
Here are the Catchr IPs that can make requests to get your data.
Please add them all to your whitelist:
141.95.207.193
54.37.80.17
147.135.136.178
147.135.137.18
147.135.137.31
You can manage the whitelisted IP here: https://app.brevo.com/security/authorised_ips