Unable to convert into float


I get the below error while working on the dataframe I am unable to proceed further. Kindly help me what needs to be done to move further on plotting.

The below is the google colab link which i was working

Please give access to anyone for the notebook.
Not able to access.

The given string has a colon (:) symbol, which cannot be directly converted into a float value.
Please try using the following: