The document is a chart for keeping monthly records, a spreadsheet.
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Are you using a Mac? I’m not a Mac user, but a quick Google tells me that the error is commonly a Mac error, and to do with timeouts.
Close LibreOffice and try to copy the file to another location before trying to open it. If you get an error during copy, the file might be corrupt or the hard disk is having problems. An issue outside of LibreOffice in other words.