DOIs not deposited error in OJS 3.0.0

Hi, Now we have a similar error, again in XML, again in Crossref.
When I try to deposit a doi in our OJS 3.0.2, and it’s checked the xml validation option, the system gives this error:

Submission was not successful! The DOI registration server returned an error: '1 - HTTP/1.1 401 Unauthorized 
Www-Authenticate: Basic realm="restricted area" 
Content-Type: text/plain 
Access-Control-Allow-Origin: * 
Access-Control-Allow-Headers: X-Requested-With 
Content-Length: 13 
Server: http-kit 
Date: Mon, 18 Sep 2017 19:03:25 GMT 
X-Rate-Limit-Limit: 50 
X-Rate-Limit-Interval: 1s 
Connection: close 

access denied'.

I am not conscious that we have modified something in the OJS system or into the code from yesterday.
Therefore, we don’t know where this error comes from.

Best,