Forms is not opening in Excel web.

[publishcaf]

Whenever I try to open the excel web of one of my forms I receive this message: 

"We're sorry. We couldn't lock this file for editing. Would you like to try again?"

And whenever I try to open a new excel workbook. I receive this message:
"Unable to create new workbooks"

I deleted history and cookies. I tried opening it from different browsers. Licenses are valid. So what is the issue? 

Has this happened with anyone before and if yes how can I edit the file again? 

[#2]

@publishcaf I'm experiencing exactly the same issue. This has effectively rendered Forms useless when needing to collaborate on the responses in Excel format. Downloading the file doesn't save changes back to the online version.