Since Plesk 11.5, you have the option to set the preferred domain for each individual domain. If this is set incorrectly, unwanted results may occur. This is especially true if certain redirects with or without www are already managed in a .htaccess file. For this reason, we generally recommend leaving the setting here at 'None'.
To make the setting, please proceed as follows.
1. Log in to the Plesk administration tool. (Forgot password?)
2. Select the Websites & Domains tab. The hosting settings are directly accessible here via a button.
3. Now under the item Preferred Domain, you can choose between None, www.domain.tld, and domain.tld.
Effects of the different settings:
- None: This setting is recommended by us and should be left at None to avoid sources of error and when no preferred approach is defined. This also applies if the redirect to www or without www is already managed in the CMS or in a .htaccess file.
- www.domain.tld: This setting causes the website to always be accessed with www. in the browser, even if the visitor enters and opens the website without the prefix in the browser. Settings or redirects set up on the website for domains without www can lead to errors here, as Plesk always adds www at the beginning.
- domain.tld: Has the opposite effect of www.domain.tld, causing the website to primarily try to be accessed without the www prefix. All settings in the application/CMS used on the website could be overwritten regarding www or without www and lead to unwanted behavior.
If you are using a CMS or are unsure which settings apply to the respective domain, this option should always be left at None.