Cannot view list of blocked users when empty username is blocked

<div class="xwikirenderingerror" title="Click to get more details about the error" style="cursor: pointer;">
  An error occurred while fetching the list of blocked users.
</div>
<div class="xwikirenderingerrordescription hidden">
  <pre>java.lang.IllegalArgumentException: An Entity Reference name cannot be null or empty
 at org.xwiki.model.reference.EntityReference.setName(EntityReference.java:215)
 at org.xwiki.model.reference.EntityReference.&#60;init&#62;(EntityReference.java:155)
 at org.xwiki.model.reference.AbstractLocalizedEntityReference.&#60;init&#62;(AbstractLocalizedEntityReference.java:78)
 at org.xwiki.model.reference.DocumentReference.&#60;init&#62;(DocumentReference.java:175)
 at org.xwiki.contrib.authentication.blocking.internal.DefaultBlockedUserService.getBlockedUsers(DefaultBlockedUserService.java:213)
 at org.xwiki.contrib.authentication.blocking.script.BlockingAuthScriptService.lambda$getBlockedUsers$0(BlockingAuthScriptService.java:99)
 at org.xwiki.contrib.authentication.blocking.script.BlockingAuthScriptService.doWithExceptionHandling(BlockingAuthScriptService.java:172)
 at org.xwiki.contrib.authentication.blocking.script.BlockingAuthScriptService.getBlockedUsers(BlockingAuthScriptService.java:98)
 at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
 at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
 at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
 at java.lang.reflect.Method.invoke(Method.java:498)
[...]