We just upgraded to APEX 4.2.2.00.11 and we are getting ORA-24247: network access denied by access control list (ACL) errors form apex_mail. This had been working correctly prior to the upgrade.
Did you upgrade from a version prior to 4.2? You may need to enable network services for the APEX_040200 user.
We upgraded from 4.1 and we even though we did enable network services for the APEX_040200 user this still does not work.
You may have additional ACLs that APEX_040200 does not have privileges to.
(YABAOAE) Yet Another Blog About Oracle Application Express: Application Express, Network ACLs and Oracle Database 11gR2
Yes, looks like that was it. Thanks.