How to Basis troubleshoot IDOCS error status 51 and status 68

Steps:

From Basis point of view, the technical problem that we have to look at is the transmission of the IDOC.
Firstly we execute BD87.
Enter IDOCS status 51 and press enter. You shall see below screen shot. As we can see, error
“Status 51″ are application or data related error.
For status 68 error, we do the same thing. Use BD87 ‘ Enter 68 on IDOC status.
As there is no error message. We double click ‘Without error message’ to see the IDOC details.
Go to status record to see what has happened with the IDOC process. As seen in the picture, the error 68 was because the IDOC had status 51 which is caused by application/data error.
Look at transaction SM58 for any hanging or error tRFC (most of IDOC use tRFC/Asynchronous). If any check the error message.
If the partner type is LS which is logical system, you can check and test connection of RFC connection via SM59.
In this case, there is no error tRFC on SM59 which proves those error are not Basis issue.