If the channel property is set, the channel it is pointing to must be the official channel. To be considered official, the channel must be named as such somewhere on the source website (doesn't have to be on the same page as the original article). https://instantview.telegram.org/checklist#6-3-3-channel-links
Read the text in link you provided carefully: "This channel link is optional."
Declined by admin
Type of issue
IV page is missing essential content
Reported
Apr 16, 2019
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If the channel property is set, the channel it is pointing to must be the official channel. To be considered official, the channel must be named as such somewhere on the source website (doesn't have to be on the same page as the original article).
https://instantview.telegram.org/checklist#6-3-3-channel-links
https://take.ms/pE0Ht