I need help fixing a specific error

Question

This is the entire message I am getting when trying to sign into my schools site. Please help!
escription: An application error occurred on the server. The current custom error settings for this application prevent the details of the application error from being viewed remotely (for security reasons). It could, however, be viewed by browsers running on the local server machine.
Details: To enable the details of this specific error message to be viewable on remote machines, please create a <customErrors> tag within a "web.config" configuration file located in the root directory of the current web application. This <customErrors> tag should then have its "mode" attribute set to "Off".
<!-- Web.Config Configuration File -->
<configuration>
<system.web>
<customErrors mode="Off"/>
</system.web>
</configuration>
Notes: The current error page you are seeing can be replaced by a custom error page by modifying the "defaultRedirect" attribute of the application's <customErrors> configuration tag to point to a custom error page URL.
<!-- Web.Config Configuration File -->
<configuration>
<system.web>
<customErrors mode="RemoteOnly" defaultRedirect="mycustompage.htm"/>
</system.web>
</configuration>

Answer 1

Many site issues can be caused by corrupt cookies or cache.
* Clear the Cache
'''[https://support.mozilla.org/en-US/kb/how-clear-firefox-cache?redirectlocale=en-US&redirectslug=clear-cache-delete-temporary-files-fix-issues How to clear the Firefox cache]''' {web link}
and
* Remove Cookies
''This will log you out of all sites you're logged in to.''
Press the '''<Alt>''' or '''<F10>''' key to bring up the tool bar.
Followed by;
Windows; '''Tools > Options'''
Linux; '''Edit > Preferences'''
Mac; ''application name'' '''> Preferences'''
Then '''Privacy.'''
Under '''History''', select Firefox will '''Use Custom Settings'''.
There is a button on the right side called '''Show Cookies'''.
If there is still a problem,
'''[https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-using-safe-mode Start Firefox in Safe Mode]''' {web link}
While you are in safe mode;
Press the '''<Alt>''' or '''<F10>''' key to bring up the tool bar.
Followed by;
Windows; '''Tools > Options'''
Linux; '''Edit > Preferences'''
Mac; ''application name'' '''> Preferences'''
Then '''Advanced > General.'''
Look for and turn off '''Use Hardware Acceleration'''.
Poke around safe web sites and see if there is still a problem. Then restart.