newly deployed computers not downloading the agent !!

hello

I have noticed this problem for a few weeks now, we deploy newly imaged computers but the agent takes about 1 week to be installed !!

Here are our configurations

• SMP 7.1
• Symantec Management Agent policy activated
• I noticed that the computers that do not have the agent are not in the filtre

Please advice the steps I could take to troubleshoot this problem

thank you in advance