nupoint fax emails , no .tiff attachments only .wav

[neoperg]

Hello,

We are setup with Nupoint fax , and receiving faxes through email. We have been receiving some fax emails with .wav and .tiff attachments, however there are some fax emails that only have .wav file but no .tiff file attachment. Would anyone know why only some emails have .tiff files but not all ?

Any help is much appreciated

Thanks!