[itsm] Package manager running error (URGENT)

Hi experts   After i have pressed Package Manager, i got the below error, pls help me, i need your help urgently   The website cannot display the page  HTTP 500   Most likely causes: The website is under maintenance. The website has a programming error.   What you can try:   Refresh the page.   Go back to the previous page.   More information This error (HTTP 500 Internal Server Error) means that the website you are visiting had a server problem which prevented the webpage from displaying. For more information about HTTP errors, see Help.