Installing the AutoSys 12.x REST API component fails with the following messages:
AutoSys REST API 12.x
The EEM server is using a self-signed certificate containing a key that is less than 2048 characters in length.
Prior to EEM version 12.6x, the certificate key length was 1024 characters by default.
New installations and upgrades to EEM 12.6x generate a self-signed certificate with a 2048 character length key.
Where EEM has been settings have been migrated from one server to another, it is possible the old 1024 key has been migrated as well, causing the reported error during the REST API installation.
You can re-generate the EEM self-signed certificate with a key-length of 2048 characters. You can also retain the 1024 key so you can use both for embedding applications.
Refer to this link for details steps on how to generate the 2048 character-length key and optionally re-import the 1024 character-length key to retain both: