Symptom
a. Install SLR license on FMC as per the steps in the config guide
https://www.cisco.com/c/en/us/td/docs/security/firepower/670/configuration/guide/fpmc-config-guide-v67/licensing_the_firepower_system.html#id_79548
b. Under Licensing tab on FMC, the page does not load and throws an error;
"An error occurred while fetching page data. Please reload the page and try again"
c. Try to enable feature licenses on managed devices under Device management, action fails with the below error;
'[error] malformed JSON string, neither array, object, number, string or atom, at character offset 401 (before "}\n\t\t\t]\n\t\t}\n\t..."'
