Subnet not able to manage e-pmp radio

We are subnetting our network to make management easyer. We have not had issues up untill the today with the following subnet which when used on the e-pmp radios with 2.1 SW cannot be managed.

The radio is set to IP: 172.16.252.1, Mask 255.255.248.0, GW 172.16.255.254.

In this configuration we try to open up the web manager page which stays blank. It responds to pings but is not manageble and only a defeult can get the radio back. We have used 172.16.240.x with a 255.255.248.0 mask with no problem on other radios, but the above network 172.16.248.0/21 network cannot be used for some reason.

Sebastian,
It appears to be a bug. Are you seeing this issue in the Firefox browser?

Can you try Chrome or IE and see if you are still having the same issue?