The table you are referring to is this one:
'Email_Status'
Status of each "Email Sent". Used to synchronize the mail dispatch process inside the OutSystems Scheduler service between multiple Servers.
It has these fields:

since the errormessage tells us you have a error in a constraint in column ID, my guess would be that the table somehow got corrupt.
Can you send emails from other applications and templates or will they raise the same error?
Your environment is on premise but i guess you can still send in a ticket for Outsystems Support?