I’m using Thunderbird 115.6.0 (Build ID 20231215200246) on Windows 7 with Gmail IMAP. Since 12th September 2025, emails from two specific senders (legal contacts) are not arriving in Gmail or Thunderbird, whilst other emails arrive normally. These contacts were emailing successfully since January 2025, with long threads. · Emails sent from Thunderbird to these senders arrive (confirmed 16th September), but their replies don’t reach Gmail or Thunderbird. · Forwarded emails from these senders arrive in Gmail when sent from another Gmail account but don’t sync to Thunderbird. · Gmail-to-Thunderbird and Thunderbird-to-Gmail test emails work fine. · I’ve checked Gmail (All Mail, Trash) and the emails are not there. If anyone can help me it would be much appreciated.