some senders cannot send me emails- 'permanent fatal errors' why?

[callko]

when some, tend to be companies rather than individuals are sending me
emails, some of them receive the folowing message-

not delivered, permanent fatal errors, can't create user output file.

I have done a system scan and all seems to be ok, can anyone help me please?

(p.s. i do not receive the emails)

 

[Brian Tillman]

when some, tend to be companies rather than individuals are sending me
emails, some of them receive the folowing message-

not delivered, permanent fatal errors, can't create user output file.

Sounds more like a problem on their end to me.