I encountered an error mentioned in title from log reader agent after reinitialize all subscription for one publication and it stopped working. This is due to replication object was not created for insert and named like 'spMSinsTableName'.
The solution for this issue, we need to create these missing replication objects using 'sp_scriptpublicationcustomprocs' which generates scripts the custom INSERT, UPDATE, and DELETE procedures for all table articles in a publication.
<pre class="brush: plain"> EXEC sp_scriptpublicationcustomprocs 'PublicationName' </pre>
after running generated scripts in subscriber database, log reader agent started to work.