Hi there! I and my colleague encounter some bugs with Thunderbird and we would like to seek your advice in regards of the issue. 1. <peggytsui@citizen-systems.com.hk> was supposed to get a cc copy of the email sent by <joanlo@citizen-systems.com.hk> at Mon, 12 Jan 2026 09:35:19 +0800 but it never reached. The receivers, namely <takehara@systems.citizen.co.jp> and <ivanwong@citizen-systems.com.hk>, however, were able to get the mail. <ivanwong@citizen-systems.com.hk> and <peggytsui@citizen-systems.com.hk> are working at the same office and under the same network. Network provider checked the protocol, router, traffic and firewall are working as normal. 2. <fionawu@citizen-systems.com.hk> found a number of emails that she kept at "Inbox" disappeared on 12 Jan 2026 morning +0800. She is unable to find it anywhere at her whole mailbox but has to ask the senders to resend them to her. It would be very much appreciated if you can check and advise how to prevent the issue from happening again.