If gateway cannot access external audit database/syslog server, the gateway cannot startup successfully --  it might be due to network problem, or the remote server is down, and so on

The problem can occur even the audit is configured to save in both internal database and external database.

Release:
Component: APIESM

For syslog server, please refer to another KB article, 
https://comm.support.ca.com/kb/gateway-won-t-start-up-successfully-if-it-cannot-reach-a-syslog-server/kb000074318

For external audit sink,  after it is enabled, there will be 3 hidden cluster properties to be added to table ssg.cluster_properties,
audit.sink.alwaysSaveInternal
audit.sink.policy.guid
audit.lookup.policy.guid

Login mysql ssg database and remove those properties to disable external audit sink,
1. backup 
mysqldump ssg cluster_properties > cluster_properties.sql
2. remove audit properties,
delete from cluster_properties where propkey = 'audit.sink.alwaysSaveInternal';
delete from cluster_properties where propkey = 'audit.sink.policy.guid';
delete from cluster_properties where propkey = 'audit.lookup.policy.guid';
3. start the gateway