The "Tally" functionality does not work for encrypted elections beyond a certain size (quote from @jrbs) via the web. This may also be true for unencrypted elections. We want to improve efficiency of the Tally functionality in this task.
See investigation task: T269029: Investigate issues with Tally function in SecurePoll [8Hr]
Related task: T271824: Improve the efficiency of vote decryption during tallying