Blocks are invisible after hosting drupal7
Sometime the issue occurs when we migrate the site. Just follow through these steps:-

1) Check the block section of the local and live site 
2) Check all blocks from the local and live
3) Now assign the blocks to the same regions in live as it is in the local setup
4) Check blocks are visible on the given region on the page or not. 

Edit the blocks to set their display settings.