please search your problem before send support request
Why my accounts are NOT sending any DMs to any of my new/followers?
you haven’t used the correct pattern for sending DM. and it causes the block by IG. Please read send auto direct message page carefully. Especially the last part of this page!
After reading that page, please change the text and picture of your message and use the pattern which is explained in the last section of that page that you read to start sending DM again.