   MAPISendMail fails on some machines
  Hello,I have been using the MAPISEndMail function and Thunderbird without problem for the last year. I need it to send automatic emails when a problematic event occurs (e.g. a device jams, etc.). I now tried to do the same with 2 other PCs, but I ran into an unexpected "Sending of message failed"-message.On all machines I have set Thunderbird as the default email application. On all machines I have the same Thunderbird settings (e.g. email account, pop, SMTP, mapi.blind-send.enable=true, mapi.blind-send.warn=false, etc.). On all machines I have the same application (my application) that calls MAPISendMail in the same way:LPMAPILOGON lpfnMAPILogon;LPMAPISENDMAIL lpfnMAPISendMail;LPMAPILOGOFF lpfnMAPILogoff;std::string emailAddress("SMTP:");emailAddress+=_destinationEmail;MapiRecipDesc recipient={0,MAPI_TO,(LPSTR)_destinationName.c_str(),(LPSTR)emailAddress.c_str(),0,NULL};MapiMessage message={0,(LPSTR)_subject.c_str(),(LPSTR)_body.c_str(),NULL,NULL,NULL,0,NULL,1,&recipient,0,NULL};LHANDLE lhSession;HANDLE hMAPILib;hMAPILib=LoadLibrary("MAPI32.DLL");lpfnMAPILogon=(LPMAPILOGON)GetProcAddress((HMODULE)hMAPILib, "MAPILogon");lpfnMAPISendMail=(LPMAPISENDMAIL)GetProcAddress((HMODULE)hMAPILib, "MAPISendMail");lpfnMAPILogoff=(LPMAPILOGOFF)GetProcAddress((HMODULE)hMAPILib, "MAPILogoff");(*lpfnMAPILogon)(0,NULL,NULL,MAPI_ALLOW_OTHERS,0,&lhSession);(*lpfnMAPISendMail)(lhSession,0,&message,0,0);(*lpfnMAPILogoff)(lhSession,0,0,0);FreeLibrary((HMODULE)hMAPILib);Following are the 3 machines I am using, only the first works (the two others display "Sending of message failed" and the MAPISendMail function returns "MAPI_E_FAILURE" ("One or more unspecified errors occurred. No message was sent.")).Machine1 (working): Win XP Prof. Version 2002 SP3, Thunderbird version 2.0.0.24Machine2 (not working): Win XP media center edition, version 2002 SP2, Thunderbird version 2.0.0.24Machine3 (not working): Win 7 Home premium, Thunderbird version 3.0.4To me it can only be an obscure Windows settings that I forgot. I should also mention that all 3 machines can send emails the manual way without problem. Also, the MAPISendMail opens on all 3 machines Thunderbird if not already open.I'd appreciate a lot if someone could point me into the right direction.   