Lately found out a solution to a very strange SQL 2016 Log Shipping issue: its LSBackup_<db name> job fails without any meaningful error message. Nothing will show in SQL or Windows log. When you check its job history, you will see the job failed with below message:
Date <date time>
Log Job History (LSBackup_<db name>)
Server <server name>
Step Name Log shipping backup log job step.
Sql Severity 0
Sql Message ID 0
Operator Net sent
Retries Attempted 0
Executed as user: <domain\user>. The step failed.
Turns out the fix to this issue is either install .NET Framework 3.5 feature on the Windows server running SQL 2016 or install SQL Server 2016 CU1.
Please refer to https://support.microsoft.com/en-us/kb/3173666 for detailed information regarding how to get the CU. The link is for solving a different but related issue (LSCopy job fails).
This fix was tested on Windows Server 2012 R2 and Windows Server 2016.