When trying to upload files from a vCenter client to a datastore in ESX  /  vCenter Server you get the error “Failed to login into NFC server”.  To solve this problem you can do any of the following:

1. Ensure there is enough space in the datastore


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2, Make sure Port 901/902 are open between the VI Client to the source of the file and/or the vCenter server.

3. Make sure the DNS configuration for the host servers is on both the machine youre trying to run the vCenter Client on and on the vCenter server on.  So the software knows where all the ESX servers are.