Email Journey Error : 'messageExecutionError', 'kafkaError', blank errors

Hi,

We have a journey where we are sending out emails. In CJA report we saw some 'messageExecutionError'. I went through existing questions highlighting same issue but couldnt find much description on what could be the cause, queries to check the details, or fixes. 

Any suggestions/advice is much appreciated

Update : I dived a bit and found that the executionErrorCode to be 'kafkaError' and in some places actionExecutionError was blank. 

I didnt even find any relevant adobe documentation detailing the issue