While connecting an incoming email account, you can choose between two options - skip all existing emails in the mailbox and only start fetching new emails received after the account is connected to LiveAgent, or fetch also all existing emails in the mailbox. If you select the second option, the system will continuously fetch all the emails from the inbox.
Emails are fetched from the inbox in periodic batches which means that fetching all existing emails can take a significant amount of time, depending on the number of emails present in the inbox. This might result in a delay in new unread emails appearing in your agent panel (especially when you are reconnecting an email account that was previously connected).
To reduce the time needed to fetch all emails, it is advisable to first move emails that do not need to be checked by the system from the inbox to an archive folder before connecting/reconnecting your incoming email account. Emails in other folders apart from the inbox are not fetched by LiveAgent, find more details in this article. When reconnecting an email account that was previously connected, the system still checks also the already fetched emails, but these do not create duplicate tickets as their IDs are already stored in the database.
The most effective way to determine if an incoming email account is actively checking the inbox and fetching new emails is to monitor the account status in Configuration > Email > Incoming Email Accounts. If everything is set up correctly, the status will refresh every few minutes (minimum 5, depending on the number of incoming email accounts), indicating that the system is actively scanning your email address's inbox.
Please note that checking and fetching several thousand emails can take several hours, or even days.