Database Mail: (Syntax error, command unrecognized. The server response was: Authentication require)

We've got SQL Server in OCI. Configured Database Mail service with Basic authentication (SSL required) with right e-mail address, server name, login, etc from OCI mail service.  But when I try to send test mail from SQL Server I get error:

The mail could not be sent to the recipients because of the mail server failure. (Sending Mail using Account 1 (2023-08-01T11:16:03). Exception Message: Cannot send mails to mail server. (Syntax error, command unrecognized. The server response was: Authentication required).)

However, when I test send mail with curl, it works (from the same DB server):

C:\Temp>curl -u ocid1.user.oc1..{user}:{password} smtp://{mail server} --mail-from test@test.example --mail-rcpt rcpt@test.example --ssl --upload-file C:/Temp/mail.txt
Warning: --ssl is an insecure option, consider --ssl-reqd instead
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100    80    0     0  100    80      0    374 --:--:-- --:--:-- --:--:--   377

Version: Microsoft SQL Server 2019 (RTM-CU20) (KB5024276) - 15.0.4312.2 (X64) Apr 1 2023 12:10:46 Copyright (C) 2019 Microsoft Corporation Enterprise Edition: Core-based Licensing (64-bit) on Windows Server 2022 Standard 10.0 <X64> (Build 20348: ) (Hypervisor)

What settings in SQL Server/Windows Server should I check? Thank you