Error with angualr strict mode

[JCLMAQ]

Hello,
I get the following error type when running Angular in strict mode (one among others):

src/app/courses/course/course.component.ts:41:9 - error TS2322: Type 'Observable<Course | undefined>' is not assignable to type 'Observable'.
Type 'Course | undefined' is not assignable to type 'Course'.
Type 'undefined' is not assignable to type 'Course'.

Do you know how to fix this error