Twitter cards no longer appear for links, they worked so fine before and we changed nothing since then.
The links don’t show any error in google console or Facebook debugger.
On twitter card validator this error appears:
ERROR: Fetching the page failed because the request timed out.
Not that, the links from the main domain work with no propblems, but not for the subdomain.
Used Card validator and it gave me the error.
Tried links from the main domain: dailymedicalinfo.com and there was no proplem !
Revised page markup and all twitter meta tags are there.
Contacted the server Admin and confirmed there is no blocking for Twitter bot.
Tried to fetch the link using other bots like -Google,Facebook- and it worked.