Cannot log into UTM 9 Webadmin

I have updated the DNS on our DNS server as follows:

Old IP

webadmin.mydomain.com = 10.10.10.10

New IP

webadmin.mydomain.com = 10.10.203.10

I have both VLAN interfaces listed above correctly.

When I navigate the webadmin logon console it will no longer accept my credentials at that new IP.  But when I type in the old IP in the address bar it works.

What could be the problem?

Thanks