Stock Prices not updating

I am using Personal Plus 2021 in Windows 10.

I have a small number of files. In most of them the stock prices have updating ok but in one, they're not. I've read through a few of the prior recommendations raised in the past for this problem but so far, no joy. I've backed up the data, rebooted, run a manual update via investing/online activities but it stubbornly refuses to update. Can someone please recommend my next steps?

Thanks very much