Problem:

My Release Management Application Pool (ReleaseManagementAppPool) is stopped and will not stay running.

Solution:

Open the ApplicationHost.config from “%systemroot%\system32\inetsrv\config” and add “preCondition="integratedMode,bitness64"” to the SPNativeRequestModule entry:

<add name="SPNativeRequestModule" image="C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\15\isapi\spnativerequestmodule.dll" preCondition="integratedMode,bitness64" />

Explanation:

This is most likely to appear if you have SharePoint 2013 installed on the same server hosting Release Management.  This issue with SharePoint may cause any 32 bit website from working.