DOI not submitting

Hello there,

Trying to configure DOI. Installed required plugin. When submitting DOI to crossref in OJS it is giving the error: Registration was not fully successful! The DOI registration server returned an error. (I have entered login details correctly).

Even downloaded xml file is also giving error while validating. Here is the error.Screenshot_1

Please help with some solution.

facing the same problem. Please help.