SharePoint 2010 – "HTTP 500 Internal Server Error" while trying to browse to a SharePoint site using Claims-based authentication {Event:8306}

After creating the site collection in SharePoint 2010 using claims based authentication, when we access the site we get the error 

"HTTP 500 Internal Server Error". For the details of this error we need to check the application log in event viewer. 

This error can be solved by the following steps.

1. Go to Start -- Control Panel --; Administrative tools –> Local Security Policy. Local Policies -- User Right Assignments -- select the Impersonate a client after authentication properties
2. Add the Application Pool account for the site which is not working, i.e. the domain\username
3. Go to the application pools in IIS and if the SecurityTokenServiceApplicationPool is stopped then start it.
4. Reboot the server or do a IIS Reset, so the changes can take effect.
5. Browse the site and it should work fine.

SharePoint error-The password supplied with the username was not correct. "Error while creating web application"

Some days back I was creating a SharePoint web application in my local machine. 
I entered all the details of the web application and when I hit the Create button, i got the following error.

"The password supplied with the username <domain\username> was not correct. Verify that it was entered correctly and try again"

This error occurs when we change the password in application pool of IIS and the password will not be updated into the power shell. 

To change the password in power shell we need to run the stsadm tool.

Step1: 
Navigate to the directory "C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\14\BIN" and run the following command. 

Step2:

"stsadm -o updatefarmcredentials -userlogin domain\username 
-password  password".

After running this command a message will be displayed as "Operation completed successfully."

Step3:
After you got this message, do a IIS reset and proceed with the creation of web application. The web application will be created successfully.