EXTREMELY IMPORTANT: Please attach a ZIP file containing your Akeeba Backup log file in order for us to help you with any backup or restoration issue. If the file is over 10MiB, please upload it on your server and post a link to it.
When updates are checked, Joomla 4 and Joomla 5 displays the message: "The checksum verification failed. Please make sure you are using the correct update server!"
A download of Akeeba Backup 9.8.2 and subsequent 'Upload Package File' works all right.
In Joomla 5, the update to 9.8.2 was shown, the online update seemed to have worked but after the iupdate the version remained as 9.8.1.
Here is the Joomla! Forum topic about the issues: https://forum.joomla.org/viewtopic.php?f=844&t=1005263