Limits with sending DMs on Follow Liker?

I am playing around wiht follow liker and wanted to figure out what the limitations are when sending DMs.

I just had it on and I got a message within the activity log that instagram is saying I am doing too many requests when trying to send DMs.

What are the natural limits there, how many DMs can I send, and how many DMs daily and what about the time in between the DMs as for delay?

Thanks guys,