Below are two known issues that can cause this:
1. The source path is pointing to a server that does not contain the actual share.
2. The source path format is incorrect.
There are two possible resolutions to this problem:
RESOLUTION 1:
1. Change the source server name to the server that contains the actual shares that are being migrated.
RESOLUTION 2:
2. Change the source path to the following format: \\Server Name\Drive$\Share\
