Hello,
If i have understood correctly you have got the SIP ALG disabled and opened all the ports for communication manually through security policies. Please correct me if i am wrong.
If the above is the scenario then the command "set security alg sip retain-hold-resources" might not be of use and it will solve the problem if you have SIP ALG enabled.
Now when you enable SIP ALG then you are not able to call your extension itself which points us to a problem with the SIP ALG. Do you have any information what the problem is as you had the ALG disabled in advance to resolve the issue.
Thanks,
Pulkit Bhandari