For AnyConnect on iOS, Follow the procedure Introduced in " How to Obtain Logs for AnyConnect (iOS / Android) Without DART "to retrieve Logs.However, May we request Additional information on the iPhone console log, DEPENDING on the failure Situation.Especially in the case of troubleshooting iOS on-demand function, follow the procedure shown below to obtain the logs.
1. Installing iPhone Configuration Utility
Go to the official Apple website, then download and install iPhone Configuration Utility.

2. Starting Up iPhone Configuration Utility
Once the installation is complete, restart iPhone Configuration Utility and connect the iOS device via USB connection.

3. Checking the Console Log
Select the iOS device Connected and click the console Tab.Make sure That the log output contains logs from the time period of the event to BE Investigated.

4. Saving the Console Log
Click "Save Console As ..." shown at the lower-right corner and Save the log.
In Addition to the logs of AnyConnect, all the logs of Other Applications and Kernel logs Are Recorded in the console log .When you retrieve logs by reproducing a failure, try not to perform operations that are not directly related.

Related Information
Original Document: https://supportforums.cisco.com/ja/document/12110511
Author: Shinpei Kono
Posted on February 26, 2014