Please try to re publish the same from your local system. If you don't have the local tableau file then download the tableau report from tableau online or tableau server and debug step by step.
Please let us know what error pops up when you open the report after downoading
I'm unable to republish the woorkbook because I got the same error.
I have the same error after upgrading Tableau server from 10.4 to 2018. Were you able to resolve your issue?