In addition to the host entry, make sure to add the appropriate regular expression for your website.
The CMS site has an attribute called urlPatterns. This is a list of regular expressions that the website CMS filters match to determine which storefront a user is trying to access.
The simplest thing is to add a further regular expression to the CMS site like the one below:
(?i)^https?://[^/]*/yacceleratorstorefront((?![\?\&]site=).)*
At run time, you can can do it in the hybris Management Console(hMC). Navigate to WCMS Website Your Site Name Properties tab and edit URL Patterns section.
To make the change permanent, add the appropriate code to the CMS site setup ImpEx script run during the project data phase of initialization e.g. for electronics storefront
# CMS Site
UPDATE CMSSite;uid[unique=true];urlPatterns;
;electronics;(?i)^https?://[^/]+(/[^?]*)?\?(.*\&)?(site=electronics)(|\&.*)$,(?i)^https?://electronics\.[^/]+(|/.*|\?.*)$,(?i)^https?://api\.hybrisdev\.com(:[\d]+)?/rest.*$,(?i)^https?://[^/]*/yacceleratorstorefront((?![\?\&]site=).)*;