Why am I being shown a server not reachable error while migrating using POP/IMAP?

Why am I being shown a server not reachable error while migrating using POP/IMAP?

If you're getting a server not reachable error, there might be issues with the server details that you entered (server name, server port etc.) while adding the migration details. Make sure that you enter the correct values before you start the migration. Learn more.