I did have a problem with this. On a new laptop running Windows 11, I couldn't configure cloud sync. After choosing Google Drive, the authentication window popped up. I entered my email the clicked Next. I then get a "Couldn't verify the security of your web browser." I retried the process, uninstalled then reinstalled (I use the Microsoft Store version), installed all Windows Updates, It took me a bit of search to discover Diarium uses Edge Web View. I then uninstalled it. Instead of using my chosen browser (the default behaviour for other apps like Dropbox, LinkedIn, Twitter, Reddit, etc.), Diarium refused to do anything related to cloud sync until the Edge Web View was reinstalled. After reinstallation (which installed a newer version), then I was successful at configuring cloud sync.