The program uses a system called MAPI to send out the invoices using your email client. This is part of the Windows Operating System and is used by many software vendors to send emails.
TPN Invoicing creates an email and asks MAPI to send it. To see the settings go into Control Panel then Default Programs. Look in 'Set your program defaults'. Find your email client and choose the option of 'Choose defaults for this program'. The MAPI section should have a tick on it. (In Windows 10 Falls update this has disappeared!)
1. If you install the 'Click to Run' version of Office365 then it can cause this to fail as it modifies MAPI and stops it from working in the same way. There is not a simple fix as you have to modify a number of Registry entries to get it back to normal.
2. If you use Hotmail through Microsoft Office and your emails stop working then it may be that Microsoft have upgraded your email server. from POP3 to IMAP. They started doing this in 2016. Previous versions used Hotmail with Outlook using the Outlook Connector software. This is now obsolete. You will need to remove the account in Outlook that says 'Hotmail MAPI' and add the account again. You will only need to know your username and password to set it up.
3. If using Office 2016 or earlier versions then it may be using the wrong MAPI file. In the case of Office 2016 go into this folder :-
C:\Program Files (x86)\Microsoft Office\root\VFS\ProgramFilesCommonX86\System\MSMAPI\1033
Here you will find a file called MSMAPI32.DLL which you should rename to oldMSMAPI32.DLL
Try the emailing again. If this fails then go into C:\Windows\System32 and locate the file mapi32.dll and rename it to oldmapi32.dll then run the program fixmapi.exe which is in the same folder.
Item 3 applies to other versions of Office. You will find an extra MAPI file in a sub folder of ProgramFiles (x86)\Microsoft Office which should be renamed.
Norman
