I checked in the SMSPXE.log file and it appears
the issue was caused by the new computer being unknown by SCCM. It states
"device is not in the database.".
From the Configuration Manager console browse to
the All Unknown Computers collection from Assets and
Compliance\Overview\Devices\All Unknown Computers highlight the Unknown
Computer object which is x64 in this instance and use the Add Selected Items
button and click Add Selected Items to Existing Device Collection.
From the Select Collection window choose a
collection that has Task Sequences advertised/deployed to it and drop the unknown
computer into there.
Try the PXE Boot again and it should have
resolved the issue.