Hello,
Besides setting "gw/acl_mode = 0", verify the other points at the following WIKI page:
Disabling gateway security - Application Server Infrastructure - SCN Wiki
Then, access the SLD:
Stop it, wait for 10 seconds, and start it again.
This is just a workaround.
The appropriate solution is to create the reginfo file with the correct rules for your environment.
For this, check out this WIKI page:
Gateway Access Control Lists - Application Server Infrastructure - SCN Wiki
Best regards,
Isaías