On Wed, Mar 31, 2021 at 11:29:04PM +0200, gde...@ngservers.com wrote: > I can't send emails while using my android smartphone + outlook.
Perhaps your phone is sending SMTP commands with non-ASCII data, but your Postfix server is not configured to support SMTPUTF8. However, more likely your phone is trying to use "implicit TLS" (rather than STARTTLS), and the non-ASCII data in question is the binary TLS client HELLO message. > Here is the debug log I can get : You have needlessly enabled debug logging, please turn it off, it is just a distraction. > Mar 31 23:23:00 mail postfix/submission/smtpd[23279]: < > pop.92-184-97-113.mobile.abo.orange.fr[92.184.97.113]: ???? This is more likely to be TLS than a non-ASCII command. > Mar 31 23:23:00 mail postfix/submission/smtpd[23279]: < > pop.92-184-97-113.mobile.abo.orange.fr[92.184.97.113]: ???? Ditto. A packet capture can confirm the hypothesis, but probably not necessary. Make sure the client is configured to do STARTTLS. -- Viktor.