You may have generated new Sku Grid remote API key but it is not identical in both Hydra and Sku Grid.  They have to be identical in order for hydra to be able to communicate with Sku Grid. 

Since they are different, your items are not exporting.   

You can follow this video to help you reset your Sku Grid remote API keys in both your Sku Grid and Hydra settings: https://www.youtube.com/watch?v=t1Gnmx39cnY 

Written directions are below as well. 

To fix it, in Sku Grid go to Settings --> Remote API, click Generate New Key.  Save the settings. Go to your remote API settings again.  Copy this newly generated key.  Be sure not to copy any extra white space before or after the remote key.  Go to a new tab with Hydra opened and click on Keys in the navigation area.  Click Connect next to Sku Grid KeyDelete the old Sku Grid remote key.  Paste in the new one that you just generated and saved in Sku Grid.  Then click the save button in your Keys settings. 

Double check to make sure the remote key is now the same in both Hydra and Sku Grid.  If it is, your items will start to carry over to skugrid in about 35 min.