Invalid format of a namespace given manually

Hello,
A couple of days ago I requested a user namespace to be manually created for me, since it was missing after first login (see this post). Thanks to quick response from galaxy developer, it was fixed, and namespace was created. However, today I was trying to publish a collection, using aforementioned namespace, and it would not let me, stating the following:

ERROR! Galaxy import process failed: Invalid collection metadata. 'namespace' has invalid format...

Can I request help with either renaming the namespace (“dvchevskii” would be fine), or somehow resolving the issue otherwise?

Here is the link to failed task: Ansible Galaxy

Thanks in advance!