I had to change the public ip address of our VPN anyconnect destination and updated DNS. My Anyconnect client is still attempting to use the old ip address when I put the FQDN in the connection field.
I have tried to uninstall and installed a fresh anyconnect program, but still happens.
Is there any local files which would be holding the old public ip address.
I have checked the host file. FYI this is Windows 10.
This could also be cached in C:\ProgramData\Cisco\Cisco AnyConnect Secure Mobility Client\preferences_global.xml depending on how the original connections were made to the ASA.
Check your ASA for a client profile. By default it is called profile.xml. It has the address and/or FQDN of your ASA hard coded in there. Even if you delete the file from your clients (in the location @RJI mentioned) it will get rebuilt upon their next connection.