Unable to reply to Instagram comments error 20

If you are seeing the error below, it is most likely due to your comments being seen as spam by the Instagram automated systems

Facebook error: This API call does not support the requested response format (code 20, subcode 1772111)

To solve this issue is very simple. Instagram might take multiple, identical messages or replies as spam due to repetition. So, to avoid this error, simply make sure you do not give repetitive answers or comments.

To elaborate:

• Avoid replying in the same manner to multiple comments, Instagram will red flag it as spam
• be creative with your comments: add more words, rephrase, say it differently each time
• Avoid using short replies or using emoticons or smileys as your only response

Take a look at the Instagram Platform Policy & its Community Guidelines to better understand the rules and regulations maintained by the platform.

Also, you might want to review the Instagram Platform policy and Community guidelines, to make sure your replies are consistent with these docs.