Http(s) boot: could not establish connection with HTTP server

Hi all!

 I am trying to leverage dell's http(s) boot to start an iPXE environment. I have this successfully running on a Precision 3460 and Precision 3450. If your question is, why not use DHCP options? The answer is I cannot. We are using dell command configure to set our machines to http boot from our boot server. This is how it works when it is successful:

1) http boot starts and pulls a DHCP address.

2) http boot establishes a connection to boot server

3) http boot gets the NBP filename & File size (the fact that it gets the file size proves a connection was established)

4) http boot downloads the NBP file in the prior step

5) http boot boots the NBP file

Happy days!

How is it failing?

1) http boot starts and pulls a DHCP address.

2) http boot establishes a connection to boot server

3) http boot gets the NBP filename & File size (again, the fact that it gets the file size proves a connection was established)

3.1) It fails to download the file and presents us with the error

HttpsBoot

Could not establish connection with HTTP server. Contact Network admin to resolve the issue.

The successful 3460 was done with the same network cable, and peripherals as the unsuccessful FCS1250. It's not the network. I updated the BIOS to the latest version. Secureboot is off. I tried another FCS1250 and got the same failure. I believe the issue is inherent in the FCS1250 firmware. The dell tech I spoke to said this was out of their scope. Not sure if this is true of firmware problems. This link was unhelpful: Http(s) Boot 

My guess is that HttpBoot successfully pulls a DHCP address, and the initial connection to the server, but when it attempts to download the file, the connection breaks. Any help would be greatly appreciated.