How to enter TOPICS in the Newsletter Popular Contents

You have already told me I cannot enter url's for forums or categories . I must enter TOPICS . I have been attempting to do that .

I keep getting :

The input value is not a correct URL

So how does one enter a TOPIC for the next newsletter ?

Dear @azwiz

can you provide some examples of the topic links you are trying to enter?

Thanks in advance

Example:  https://help.forumotion.com/t161012-happy-new-year-s-eve#1125911