Apologies for the delayed reply.
Regarding the issues, it looks like it is related to the file permissions on your server:
Please note that Joomla! should be configured with 755 for its directories and 644 for its files except configuration.php should be set to 444 once you have configured your site (extra security).
Please check with your server administrator and ask to set the file permission accordingly.
Please let us know if you face any issue.
The administrator has disabled public write access.