It should be straightforward:Adobe Experience Manager Help | Import and manage applications It is a well-formed .xml file ? no syntax error ?

It shows a failed login attempt. Whats special about it ? Do you think this is not a correct entry in the log ?Can you debug for the following package as instructed in the logs:com.adobe.idp.um.businesslogic.authentication

I dont believe its known ... agreed with Jaideep

Check package dependencies to make sure there is nothing missing:http://localhost:4565/system/console/depfinder

Backward Compatibility in AEM 6.5

Do you want to process the json output to eliminate the repeating property or you want to get the json output without the repeating property at the first place ?

You can always do an offline backup. This requires a downtime of AEM, but can be quite efficient in terms of required time compared to an online backup.Backup and Restore

Does it also happen in private mode (incognito) ?

When you open the page for edit you can change the mode from edit to developer mode where you can see much more details about the components.

Are you assuming a new certificate is already generated to upload ?