Table gridlines

I set up a table in Microsoft 365 Office and could see all the gridlines within the table. But when I opened it today, all the gridlines have disappeared. Forums say click Table Layout, then View Gridlines, but I have no button that says View Gridlines (that must be on old versions of Word). I managed to find the Borders and Shading tab, and clicked on All Borders, colour black, but the lines still don't show. I know what the little button that will make lines show looks like, because I use it with my Excel spreadsheet, but it doesn't exist on the ribbon on my Word tables.