Folders missing in sidebar

Hello folks,

I just recently installed Thunderbird on a fresh installation of Windows 10 and connected my icloud.com email address to it. At first, everything seemed to work successfully, but when I finished the setup process, I was surprised to find out that some of my folders were completely missing from the sidebar. I can clearly see them in the icloud.com webmail client, but they’re nowhere to be seen in Thunderbird. How can I restore them?

Please help! Thanks!