As you are using the section from the different class hierarchy you should provide the page context accordingly while adding the section. Can you share the properties of your subsection which is included in mainsection along with the data available in subsection.
Santosh - which version of pega you are using. I tried to create Data type OTHO2I-Data-EmployeeDT and i am trying to refer this in my OTHO2I-CSSA-Work-Section1 repeat grid via Source -> Property and List/Group -> .Employees.
But i am not able to use the .Employees in this section as shown in the attachment, so can you checkout the Section 2 and see if you are able to save it with this configuration.
No.still it shows the same..but runtime there is no issue with that section.Initially I added some fields to the process steps,by default section was created and named SelectOfficeEquipment_0.Later I need to add a data type named Facilities to that section.so the new section is created named SelectOfficeEquipment_0_Facilities.
Here SelectOfficeEquipment_0 section has the cannot render section error.