HTTP error 401 message when trying to add items

Fairly new user of Omeka, but managed to turn on error logging when I kept on getting the generic error message each time I try to add an item to a collection. I'm hosting Omeka on Reclaim, and the error message seems to be related to something on Reclaim's end. Has anyone else encountered/solve this?

Error message:
HTTP error 401
Invalid security token

The requested URL does not contain your session’s correct security token.

You may have reached this error by copying and pasting a URL from a different cPanel, WHM, or Webmail session into your browser’s address bar. To resolve this situation, please take one of the following steps:

Go back one page and reload the URL, making sure that the /cpsess.../ section of the URL remains the same.
Re-enter your account’s password below. This will assign your session a new security token. This new token will prevent you from using other pages of this application that may be open in other tabs.

Request information

Requested page: 404.shtml

Username:

Password:

That doesn't look like one of our error messages, so first instinct is to agree that it is on Reclaim's end. In addition to the suggestions in the message, you might try a different browser, at least to help diagnose the issue.

Just to double-check, this happens when you try to add an item in Omeka, not when you try to do something in CPanel?

Thanks for the reply--I will follow up on my message to the folks at Reclaim to try to resolve the issue.

And yes, the issue is when I try to add an item in Omeka, not when I'm working in CPanel. Thanks for asking for clarification since I was a little flustered when I wrote the first post.

Understandable. Let us know if there is any follow-up information from Reclaim that sounds like there's something amiss in Omeka.