If you are determined to find this specific legacy version for compatibility reasons, you will have to search for the filename on specialized forums or archives, but you should proceed with extreme caution and scan any downloaded files with a tool like VirusTotal before running them.
The most secure method to access After Effects is through the Adobe Creative Cloud desktop application. Subscriptions offer: Guaranteed clean, virus-free application files. adobe after effects cc 2015 1370 portableby robert link fix