warning: backoffice generated robots.txt total blocks access to site

[peter4661]

Recently we upgrated Prestashop 1.6.x to 1.7.4.2.   In finishing the installation we regerated .htaccess and robots.txt through the backoffice.

When visitors to the site continue to drop we started the search for potential cause,

With Google webmaster tools, search console / crawl,  using Google robots.txt tester reported All URL Blocked !!

Fresh backoffice generated robots.txt contained no follow instruction for the whole site:  Disallow: */

Looking further  Googlebot type: Desktop (render requested) robots.txt it also blocked access to two folders for search engines to render the site properly:
Disallow: */css/  and Disallow: */js/

It is adviced to check, your robots.txt when fresh regenerate from your backoffice.

Could reproduce this behaviour. Bug report generated.