Running K9 Version 5.600 on Android 8.1 I've noticed for several months that when using "Reply All" to multiple cc. recipients the reply gets rejected/bounced from the receiving servers This only happens with K9 - using "Reply All" on my laptop (MS-Outlook) works fine
One of the bounce replies contained the reason described below... So it looks like the reply all doesn't send a "from" header causing, them to be rejected as potential spam >>>>>>>>>>>>>>>>>>>>>>>>> This is the mail system at host ofarelay01.hostedemail.com. I'm sorry to have to inform you that your message could not be delivered to one or more recipients. It's attached below. For further assistance, please send mail to postmaster. If you do so, please include this problem report. You can delete your own text from the attached returned message. The mail system <nmsilverberg @ googlemail . com>: host gmail-smtp in . l . google . com[74.125.192.27] said: 550-5.7.1 [216.40.42.17 11] Our system has detected that this message is 550-5.7.1 not RFC 5322 compliant: 550-5.7.1 'From' header is missing. 550-5.7.1 To reduce the amount of spam sent to Gmail, this message has been 550-5.7.1 blocked. -- You received this message because you are subscribed to the Google Groups "K-9 Mail" group. To unsubscribe from this group and stop receiving emails from it, send an email to k-9-mail+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/k-9-mail/ec6decb6-be02-4cf6-8ccf-ab3875bb19e1%40googlegroups.com.