Problem on Product Backend editing function [A server error occurred while loading the tabs: ]

[jecam16]

Please help!

It was working properly but then this error appeared when I try to modify any product on the backend:

"

A server error occurred while loading the tabs: some tabs could not be loaded.
Please try again by refreshing the page.
If you are still encountering this problem, please check your server logs or contact your hosting provider for assistance.

"

 

The logs on the browser shows the following:

 

jquery-1.11.0.min.js:4 [Deprecation] Synchronous XMLHttpRequest on the main thread is deprecated because of its detrimental effects to the end user's experience. For more help, check https://xhr.spec.whatwg.org/.
send @ jquery-1.11.0.min.js:4
/adminerCVI/undefined&ajax=1&rand=1510276292839?_=1510276287874 Failed to load resource: the server responded with a status of 404 (Not Found)
/adminerCVI/undefined&ajax=1&rand=1510276293620?_=1510276287875 Failed to load resource: the server responded with a status of 404 (Not Found)
/adminerCVI/undefined&ajax=1&rand=1510276294335?_=1510276287876 Failed to load resource: the server responded with a status of 404 (Not Found)
en-default-cart_default.jpg Failed to load resource: the server responded with a status of 404 (Not Found)
/adminerCVI/undefined&ajax=1&rand=1510276297872?_=1510276287880 Failed to load resource: the server responded with a status of 404 (Not Found)
/adminerCVI/undefined&ajax=1&rand=1510276298438?_=1510276287881 Failed to load resource: the server responded with a status of 404 (Not Found)
/adminerCVI/undefined&ajax=1&rand=1510276299056?_=1510276287882 Failed to load resource: the server responded with a status of 404 (Not Found)

 

Anyone has experimented something like this?