After restarting the MOM, APM CE (CEM) cannot connect to the APM Database. If you look at the Database setting in APM CEM, you see the password has doubled in length and the test connection fails.
The problem is in the code and it is re-encrypting an already encrypted password.
To correct this issue. we have created a hotfix. This is included in the APM10.5.1HF36_DE312165. To get access to the file, open a Support case at http://support.ca.com and request this hotfix.
As a temporary work around until you get this Hotfix, reset the APM Database password, then test and save. Once you have the correct password saved, then you can make a copy of the tess-db-cfg.xml in the <EM Home>/config folder. If needing to restart the MOM again, replace the tess-db-cfg.xml with your working saved copy to get everything back to normal.