Google Merchants Center "robots.txt on the server is unreachable"
I have about 6 month using google merchants center and google ads.
and today I get this issue "
robots.txt on the server is unreachable
" I know this file is not required, and this not exist in my server, but i have created it, but google continue showing the same message.
I have another site, with similar data and this is working fine. 
Check the URL path to the file to confirm it is reachable from your browser. https://www.yoursite.com/robots.txt
If you uploaded it today there will be some lag time within the Merchant Center. If you don't see a change in 2-3 days you can reach out to Google support and request they trigger a crawl to reach the file.
no, i upload the image here in stackoverflow jaja, but i have uploaded the feed... six month ago... and today appears this issue..
Google recently crawled your site and found the robots.txt was not reachable. If you added the robots.txt today there will be a delay before the warning is removed from the Merchant Center.