Must specify the metadata fileThis error can be returned when the Meta-xml file is not found on Git (Promotion Branch) when deploying.
This is a generic Salesforce error. Somehow, the corresponding Meta-xml file for the component you are deploying doesn't exist in Git (Promotion Branch).
This could be due to:
1. The file was not created in Git when the component was committed the first time.
2. The file was somehow deleted.
Please review the branches in Git to see if the file exist in Source branch, Feature branch and Promotion branch. You might need to either commit the component again so that the Meta-xml is created or create the file manually in the branches.