Looks like this template Lab Inventory Management - Grist - is it your own copy? Any access rules added? Do other pages work?
Thank you for replying so quickly. Yes, I have full access and have been working on it for a while. It just happened after I added quite bigger amount of data (around 150 names) and I I made a mistake, then I pressed undo and it’s gone.
That’s strange. Have you tried reloading the webpage? If you open the developer console are there any errors?
If you can access the “Settings” page (in the Tools area on the left) then you could force a reload of the data engine.
It is hard to help without looking at your document. You could contact Grist Labs support at support@getgrist.com and share your document with them if you’re willing so they can look at it and help you out.