ASA5510 configuration

Can someone help me out. I am configuring a cisco ASA5510, after configuring all the interface, on configuring the Access rules, it is rejecting my subnet mask of 255.255.252.0 for a 172.16.10.1 network address. It also reject the subnet of 255.255.255.248 of my internet service provider.
the inside network cannot brows the internet.