How to correctly form a request to api vk?

Question

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From an open group, the response comes normally through this request

https://api.vk.com/method/wall.get?owner_id=-1&filter=all&count=30

for closed, when adding an access_token with the rights of wall groups, etc., the person who is authorized in the group sends a message about the captcha. I add the captcha number and the code in the request comes the same.
please tell me how to display the posts of a closed group

Answer 1

Any api vk method at any time can throw a captcha.
https://vk.com/dev/captcha_error
If you answer the correct captcha, everything will be ok.
Sometimes you need to enter captcha several times in a row