Each function event is logged in an Azure Table Storage service. Every month, a table is created with the name AzureWebJobsHostLogs<Year><Month>.
As part of troubleshooting, if you would like to get more details on any error, you first find the Id field in the Invocation details section, as shown in the following screenshot:
Look for that data in the RowKey column of the AzureWebJobsHostLogs<year><month> table, as shown in the following screenshot:
As shown in the preceding screenshot, you will get the log entry stored in the Table storage. Clicking on the row will open up the complete details of the error, as shown in the following screenshot: