unable to empty e-mail trash

Yes VazWaz, I have only accessed my mac.com e-mail account through my web browser (while using my newest (2018) powerbook) as I haven't wanted to fill up my hard drive with all of my older e-mails (by using the built-in mail app). I used to be able to delete my unwanted e-mails until about a month ago - around the time that I upgraded to the newest Mac OS Big Sur 11.5.2. This "upgrade" also caused unwanted troubles for me with my scanner (as my powerbook refused to recognize me as the administrator of my own computer and denied me "permission" to access my scanner). I've got that problem fixed, but would sure like to permanently delete all of the e-mails I've moved to my trash during this past month. Thanks for recognizing that we have the same problem while entering our e-mail accounts through our web browsers. I should have mentioned that in my original post.

Thank you Rob_H1. I followed your link to your suggested solution and realized that this would be a solution for me if I was having problems deleting unwanted e-mails while using my mail app to access my e-mail account. However, I've only been accessing my mac.com e-mail account through my web browser since purchasing my latest powerbook in 2018. Do you have any other tricks up your sleeve for this situation (i.e., emptying my e-mail trash while accessing my e-mail account through a web browser). By the way, I usually only use my Firefox web browser to access the Internet. I will try getting into my e-mail account through Safari and Chrome to see if they help with this situation. Since I still don't own a cell phone, all of the recent upgrades have seemed unnecessary for my needs and equipment.

Thanks again Rob_H1. I must have been typing my last reply to you when you were sending me your second solution set (after recognizing that I was using my browser to access my e-mail account). I've regularly gone to the sidebar and clicked on the "empty trash" command to manually delete my unwanted e-mails when their number and file sizes were unnecessarily large. However, since upgrading to Big Sur 11.5.2, whenever I try to do this, I get a dialog box that says, "Cannot empty folder. This folder cannot be emptied at this time. Try again later." I haven't previously noticed that my e-mails were ever "automatically deleted" after sitting in the trash for 30 days, as I've never let them sit there for that long. However, at this point (Aug 23rd), I now have a large number of months old e-mails that I cannot manually delete, or empty from my trash, and I am trying to keep my stored icloud data under the maximum limits. Perhaps I will have to use VazWaz's suggested solution (i.e., moving my trash contents to a temporary folder - and then deleting that folder) to keep my account within the 5 Gb icloud storage limit? Thank you again for your input and suggestions.