Might it be that this issue is related to expired account as discussed here?

Why do we get bounding box error on adding a WMS link and no image shows? On editing the preview option to Extended_preview, No bounding box error shows but still image data not displayed.

If not, please let me know, which account you are using, to check.

No, tried with an active account.

Can you share with us, which user you were using?

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  Since my bhavna_chops@yahoo.co.uk account expired, could not do further R&D so, created another account bhavchops70@gmail.com for testing.

  
  


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  if image data gettng displayed in “preview” window of configuration utility then it should work in “View in playground”. But not happening.

  
  

The reason for this behavior was in “Map bounds” settings. You have configured the instance to only show area around India. When using “Open in Playground”, the Playground app opened somewhere in Africa. By moving to India (e.g. by searching “India” in location search) it worked.

Now I removed the “Map bounds” settings, so that it works immediately.

Unless you want to limit your users to only see specific area, there is no need for this setting.