User is attempting to enter time to a project, but the project is grayed out.
You can be encountering this issue because of the project type. When a project type is Main, it is a parent project that has multiple phases billed for time and expenses at the phase level. Projects of this type can not have time or expenses billed at the parent level. To fix this issue, you can assign the project phases to your employee, allowing the employee to submit time to the appropriate phase. Another option is to change the project type to Standard. Standard projects can be a parent or stand alone project with or without phases. Check Core Help Center for details on the Type field.