SQL Server Agent unable to view network drives


I am unable to get agent jobs to output to a network path. I have pushed the IT guy to set up a domain authenticated user that logs in when the agent starts. That login does have access to the domain and is able to see the network drives. If I set the location of the output file to be the local c: then this works without issue. However if I set the drive to be a network location I get the following message;

[SQLSTATE 01000] (Message 0)Unable to open Step output file. The step succeeded. 

Any help would be very much appreciated