Do you have access to the DC? Verify that the account exists, check what permissions it has. Hopefully something like a service accounts group or so. check the security of the network location. Verify that the service account or a group that the service account is in has access there. Read and write depending on what level of access is required.

Verify that both servers, the SQL server and the target network location, are connected to the domain controller. If they are not, you won't have a like account to use. Try and go that route if you can.

A few things need to be checked before you know exactly what to fix.

1) Is the SQL Server on the Domain Controller.

2) Is the network share / file share on the Domain Controller.

3) Can both servers talk to each other across 445 (can you move a file back and forth with your account)

3.5) If you can, is your account a domain account or a local account.

4) Verify the security section of the network share. See if what groups have access to it.

5) verify the SQL Service account, see what groups it has access too.

If the file share is not on the domain, you cannot use a domain account there. You may be able to use the same account name with the same password in both places as a local account....

Honestly, if you have too much trouble with the above, I would not attempt adding accounts. I would leave it to the SA's. If there's a huge pain getting them involved to fix their side, make the problem known as something you cannot resolve without more cooperation. There's a lot more that goes into getting this stuff working. Are you in the states? If so, I don't mind going through PM's or a quick call to see if I cannot help figure it out quicker. As long as you've got the information for 1-5 first that is 🙂