If the Asset you are looking to complete EoM on is not on the EoM Register some of the following reasons could be the cause.
Note: You will require the "Edit EOM" User permissions.
Start by checking if a Hire has been created for the Asset and the hire has been marked as "On Hire".
For instructions on how to "Create a Hire", read the below article
For instructions on how to "Award a Quote", read the below article
For instructions on how to "On Hire" an Asset, read the below article
Confirm the date range for EoM processing correlates to the dates the Hire is active for.
Ensure there are no unwanted filters applied in the toolbar.
Have you refreshed the EoM page since adding or making changes to the Hire Register?