If you are using Cisco ASA, you most likely will also have certificate(s) installed. This is what you need to pay attention to (Version 9.1, higher versions might behave differently):

In the last week I was tweaking the logging setup of our Cisco ASA firewalls at work and find out why it didn’t work in the first place and how to disable “unneeded” messages. Again this post is nothing you won’t somewhere on the Internet or in the Cisco Documentation or by cafefully looking the ASDM interface. First you need to setup to which server you are want to log. The settings should be pretty straight forward.