http://<MP_FQDN>/SMS_MP/.sms_aut/?<parameters> Common causes of Exit Code 14:

1. Overview Error Message: Unable to download PXE variable file. Exit code 14

http://<DP_FQDN>/SMS_DP_SMSPKG$/<PackageID>/variables.dat or

The variable file path typically resembles:

PXE boot of a client machine in a Configuration Manager (SCCM / MECM) task sequence deployment.