Help! I upgraded to macOS Monterey now I can't read my emails [View all]

During the upgrade there was a box to check & enable Mail Privacy Protection, like an idiot I went ahead & checked it. Now when I open mail all I can see is the headers. I went to Mail/preferences/privacy and cleared the boxes that enable MPP. It doesn't do any good, even when if close Mail and restart the computer. Where are my messages & how can I get them back??? Can anyone here help?