On 2/22/2018 3:28 PM, Frank-Rainer Grahl wrote:
Currently this points to a yahoo mail server issue and not to a
SeaMonkey or Thunderbird problem.
Try setting mail.strictly_mime to true and see if it solves your problem.
I think someone at Yahoo/ATT fixed it. As of 6:00 CST 2/22 my outbound
emails sent through SeaMonkey do not exhibit the problem.
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