I created a playground for a challenge but did not connect to it to reset the password and it expired. Now i am seeing the option of only an Org that was not reset for password and I am not able to change the connecting org? Please help. Thanks!

@Subashini Thomas if that is this kind of playground, you can only have one of a kind in parallel. So if you cannot log into it (from the module, or from your hands-on orgs page as it was not connected) and did not receive the password reset email (to the mentioned yahoo.com email address), then you need either to wait for the playground to expire (and maybe clean your browser cache or try in incognito mode after then) or submit a case to support (https://help.salesforce.com/s/case-submission ; that might take more time than the playground expiration time). 

Eric