Hi,
Each managed certificate has it’s own log file. These are kept under C:\ProgramData\Certify\logs and you can also view each individual log from the Open Log File button.
The session.log also has some high level activity info.
In addition you can register your instance to the certifytheweb.com dashboard to have an overview of certificate statuses as/when they are renewed.
You can optionally perform custom scripting or call webhooks on success/failure.
Regarding renewal failures, by default failures will be reported to our API (if Status Reporting enabled under Settings) which in turn will email you - based on the email address under Settings - if/when problems occur.