Why are all of my proof versions "View Only"?


Until this morning we were using the proofing feature, it was fantastic. I went on the sheet today to create new versions of several of our proofs but the "Create new version" button is greyed out (so I can't click on it) and all previous versions are now "View Only". I'm not sure why this has happened, but it is happening to all users of the sheet. I have even tried deleting a previous version to see if that would unlock the "Create new version" button, but it doesn't. We have so much important information in this spreadsheet that we can't afford to lose as we are in the middle of creating a new product guide for our business. I have put in a support request but I am in urgent need of help as I am on restricted time to complete this job. Can anyone help?