Hello ivan,
I think I have come a little closer to the matter.
When I create a new mail, the encoder of EASenmail is called and the subject is coded correctly.
    oSmtp->HeaderEncoding = 1;   
    oSmtp->AuthType = AuthXoauth2;
    oSmtp->UserName = strKonto.AllocSysString();
    oSmtp->Password = accessToken;
    oSmtp->FromAddr = strFrom.AllocSysString();
    oSmtp->ReplyTo = strReplyTo.AllocSysString();
    oSmtp->Subject = strSubject.AllocSysString();     // _T("Rückstandsliste")
    oSmtp->BodyText = strMailBody.AllocSysString();
    Receiver see Subject: Rückstandsliste        <----- ok
But if I load an existing mail with LoadMessage() and change the subject, , it seems that the encoder is not called.
    oSmtp->LoadMessage(strEMLFile.AllocSysString()); <-------------- stored from EAGetMail
    oSmtp->HeaderEncoding = 1;   
    oSmtp->AuthType = AuthXoauth2;
    oSmtp->UserName = strKonto.AllocSysString();
    oSmtp->Password = accessToken;
    oSmtp->FromAddr = strFrom.AllocSysString();
    oSmtp->ReplyTo = strReplyTo.AllocSysString();
    oSmtp->Subject = strSubject.AllocSysString();     // _T("Rückstandsliste")
    oSmtp->BodyText = strMailBody.AllocSysString();
    Receiver see Subject: R?ckstandsliste               <--------- failure    
As a workaround, I use another encoder before assigning the subject. 
easendmail_v7909
eagetmail_v5258
ActiveX
Thank you for your help
Greetings
-Uwe
                      Edited by user
                       
3 years ago
 | 
Reason: wrong version of easendmail - corrected  7909  and 5258