he meant go and edit your profile, and change custom url to anything else.
ex: http://psteamcommunity.yuanyoumao.com/id/gghx7
http://i.imgur.com/OU1cduP.png

Actually you already got the cards, but they just not given to you yet,
same as you play the game normally,
the "New cards" notification will send to you after you close the game,
also there's countdown timer under the IdleMaster window,
it will check automatically each few minutes if there was any new card you obtained

head to this folder
C:\Users\username\AppData\Local\IdleMaster
and remove all stuff inside, that's where config file is
maybe will fix it

maybe something corrupted, try this:
1. close Idle Master
2. go to this folder
C:\Users\<username>\AppData\Local\IdleMaster
3. remove all folder you see, ex. IdleMaster.exe_Url_xxxxxxxx
4. start idle master

try change your steam language to english

do you have any game that have trading cards and it's not depleted yet

otherwise,
go play TF2 or DOTA2 and some else game like that,
they drops weapons, skins, items, which you can sell on market for buy some trading cards later

most free games requires you to spend some money in their game for getting card drops,
that's how they getting funding on developing free games,
you should search giveaways on google to find some website that gives "not free game" for free

not sure what happened, giving you some common solution

• Re-download the idle master
  
  
• Change idle master compatibility
  https://support.microsoft.com/en-us/help/15078/windows-make-older-programs-compatible
  
  
• Run as administrator
  
  
• Use "All in One Runtimes" software to install/fix required runtimes on your system
  https://www.google.com/search?q=all+in+one+runtimes