Google crawlers can't access and index our site if we use session id.Is it true or false?then share the reason for that please?
Google cannot crawl the protected content- the one users need to login to access to (except if you allow users coming from Google to see it). Regarding session id's - the problem is opposit one - if it gets to crawl all the different session id's it will essentially crawl very many versions of the same page. It should understand it is not really duplicate content issue, but still it is a negative thing from point of view of SEO.
It is very difficult for crawler to crawl url having session id, so it is better to create user as well as search engine friendly url.