APEX

hi guys,

When I run the following code to check if the mailbox configuration is correct,

begin
 apex_instance_admin.validate_email_config;
end;
/

I get this error,

ERROR at line 1:
ORA-29279: SMTP permanent error: 502 Invalid input from xx.xxx.xxx.xxx to
xxxx.xx.com.
ORA-06512: at "APEX_230200.WWV_FLOW_MAIL", line 1347
ORA-06512: at "SYS.UTL_SMTP", line 57
ORA-06512: at "SYS.UTL_SMTP", line 142
ORA-06512: at "SYS.UTL_SMTP", line 446
ORA-06512: at "APEX_230200.WWV_FLOW_MAIL", line 1331
ORA-06512: at "APEX_230200.WWV_FLOW_MAIL", line 2656
ORA-06512: at "APEX_230200.WWV_FLOW_INSTANCE_ADMIN", line 1882
ORA-06512: at line 2

And I've configured the mailbox and wallet.

orapki wallet add -wallet apex_wallet -cert 'xxxxxx CA - SHA256 - G3.crt' -trusted_cert -pwd xxxxxx

how can I fix it?

thanks.

Does anyone know? Or is APEX's mailbox feature not easy to use?