Junos OS and Junos OS Evolved support encryption method for configuration secrets using a master password. The master password derives an encryption key that uses AES256-GCM to protect certain secrets such as private keys, system master passwords, and other sensitive data by storing it in an AES256 encrypted format.

The TPM chip is available on the SRX300, SRX320, SRX340, SRX345, SRX380 SRX5400, SRX5600, and SRX5800 devices. Hence the error you are obtaining as the SRX1500 does not provide support for this feature at this time.

You can reference to the following links for more information: Using Trusted Platform Module to Bind Secrets on SRX Series Devices, and also our Feature Explorer site.