According to the developer documentation clients are allowed to make 5000 requests per hour, but at the moment my application is being limited to 350 requests per hour. The error code I get is 400, and the message is "The number of maximum requests per hour has been exceeded. You have made XXX requests of the allowed 350, in last hour.". Do you know why this request limit is in place, and how it can be increased to the listed 5000?
Note: My application uses the API to like certain images, but according to the documentation I should still get 5000 requests per hour.
5000 is total number of API requests(any instagram APIs) you can make per hour using a access_token, however certain APIs like Commenting, follow/unfollow, liking have its own limit of 350 or something to limit spam. 5000 limit is for total API calls per hour (recent photo api + search APIs + like API +...)
See the official documentation API End User Limit for more details.
The 5000 per hour limit refers to authenticated requests, ie: those which use an access_token. Since you're not using an access token, you're limited to fewer requests per hour. From their documentation:
You are limited to 5000 requests per hour per access_token or client_id overall. Practically, this means you should (when possible) authenticate users so that limits are well outside the reach of a given user
来源：https://stackoverflow.com/questions/17362562/increase-350-request-limit-for-instagram-api