Core issue
This issue occurs due to the presence of Cisco bug ID CSCsd58083.
The %CRYPTO-4-IPSEC_AAA_START_FAILURE: IPSEC Accounting was unable to send start record error message is received when stop-only Authentication, Authorization, and Accounting (AAA) is configured for EzVPN clients.
Note: This error message is purely cosmetic, and this issue does not affect functionality at all.
Resolution
To resolve the issue, configure the start-stop accounting command in order to remove the message.