This message is coming from the Google Webmaster Tools (section Blocked Resources); has anyone an idea why this happens? Is this something to correct (if so, how this could be done?). Thanks for your collaborations
Please find the google Blocked Resources Report in that How to unblock your resources
To unblock your resources:
- Open the Blocked Resources Report to find a list of hosts of blocked resources on your site. Start with the hosts that you own, since you can directly update the robots.txt files, if needed. You might not have control of all the hosts that we list, but change the ones that you can.
- Click a host on the report to see a list of blocked resources from that host. Go through the list and start with those that might affect the content and layout in a meaningful way. Less important resources, such as tracking pixels or counters, aren't worth bothering with.
- For each resource that affects layout, click to see a list of your pages that uses it. Click on any page in the list and follow the pop-up instructions for viewing the difference and updating the blocking robots.txt file. Fetch and render your page after each change to verify that the resource is now appearing.
- Continue updating resources for a host until you've enabled Googlebot access to all the important blocked resources.
- Move on to hosts that you don't own, and if the resources have a strong visual impact, either contact the webmaster of those sites to ask them to consider unblocking the resource to Googlebot, or consider removing your page's dependency on that resource.
Note : content copied from google.