Problem reaching google-email-adress with K9 (vers. 5.60)

I’ve made the nearly complete transition to (status: " early adopter"). While writing (friend with a gmail-adress)
I get this error-mesage:

This is the mail system at host

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

*********** host[]
said: 550-5.7.1 [ 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. Please visit 550-5.7.1 550 5.7.1 and
review RFC 5322 specifications for more information. i12si45690763wrn.69 -
gsmtp (in reply to end of DATA command)

Now, my question:

  • temporarily technicals problems at /e/ ?
    -> yesterday the same adress was perfectly reachable…

Thanx for your suport,
Christian Oelte

Hi @npfp there is no blocking from /e/ side. I just tested this by sending myself a mail from /e/ account to gmail account and responded and received both the emails within seconds.
Please could you try again after some time and let us know.