How long does it take to update the mail tracking?

During online voting or live voting, how long does it take for the configuration tool to update the mail tracking?

When an e-mail is sent, the configuration tool waits for a response from the server that receives the e-mail addresses. Upon confirmation that the mail has arrived, the configuration tool displays a green check mark next to the e-mail address. If the checkmark does not appear, this does not mean that the e-mail was not delivered, but only that the receiving server did not respond. It is therefore possible that an e-mail was delivered, but no green checkmark appears in the configuration tool.