I would like to know why regular expression extractor in JMeter is not extracting the data after parameterization. Response message: Internal Server Error
Your regexp is probably wrong.
To debug it, run your test then use View Results Tree and select Regexp Tester:
You can then test your regexps and see what happens.
As I don't have the response content that contains the 2 tokens, I can only guess that regexp should be :
name="__EVENTVALIDATION" id="__EVENTVALIDATION" value="([^"]+?)" , see https://regex101.com/r/aG1gX2/1
name="__VIEWSTATE" id="__VIEWSTATE" value="([^"]+?)" , see https://regex101.com/r/iM5cZ3/1