I can't close one tab in Safari

I can't close one tab in Safari. Details: Mac Air 13", 2017, macOS Big Sur version 11.2.3, and using Safari Version 17.0.3 (16610.4.3.1.7). I am able to have several tabs open and am able to individually close the other tabs. The problem tab is smaller than the others in terms of length, unless selected, and is already at the tab bar after closing and re-opening Safari. I've quit and restarted Safari, quit and restarted the entire computer, and updated the software to no avail. At this point, closing this tab has become a personal vendetta - would love additional input.