If you ever bumped into this issue when your custom SharePoint Page Layout cannot be rendered properly. You may try the resolution steps below

Description: An error occurred during the parsing of a resource required to service this request. Please review the following specific parse error details and modify your source file appropriately. 

Parser Error Message: Only Content controls are allowed directly in a content page that contains Content controls.

In SharePoint branding journey, you often need to create your custom page layout to present your article base on Designer’s template file.

And if you are doing it, there is 1 important thing that you should Avoid doing. And that is to Auto Formatting your PAGE LAYOUT!

If you have not noticed (probably you haven’t because you found my article!)

Once you auto formatting your Page Layout via Visual Studio function  CTRL + E + D

<asp:content contentplaceholderid=”PlaceHolderPageTitle” runat=”server”>

See clearly, there is a problem with the Tag above. the “c” for content is auto formatted to be lower case! It matters! Lower c and Upper C make a huge different! It took me one whole one to try out and fix this issue!

Resolution

If you want to make use of the auto formatting (to tidy up your code) please remember to REPLACE ALL (CTRL + H) for “asp:content” to “asp:Content”. Make sure your match case is checked when replacing all

Jeez!