Is there a way to read deffered mail from /var/spool/postfix/deferred. I tried to copy file to my mail directory and see it from webmail but it dosnt work. When im using less or cat it seems like files in spool/deferred are some binary files.
You need to get the message id first with
postqueue -p then once you have the message id you read it with
postcat -q messageid. Of course replace messageid with the actual id you find.