Hello Abhijit!
First - welcome to the community!
First thing I’d ask is if you’ve set the visualization as the default visualization in your mappviewCfg file?
Setting this is an often missed step and will result in the same behavior you describe.
This section of the help also describes this step.
As a side note: you can additionally navigate directly to the visualization without it set as a default visualization with the url localhost:81/index.html?visuId=myVisu replacing ‘myVisu’ with your visualization’s ID. Described here in more detail.