Most of the time files you uploaded might be over root user through ssh, if you did not used a web panel user account for uploading them and folders/files permission are not properly set on public_html as they needs to be 755 for folder and 644 for all files.
Run these commands as root user from ssh terminal and it will fix folders and files permission. Make sure to run this inside your public_html folder where script files exists. Otherwise whole panel system might go broken and you have to start from fresh!
So move to your public_html folder first as a root user!
cd /path_to_your_Public_htmlTo fix user owner from root to your web panel user who owns all contents of public_html folder and their all of their permissions. you have to use these command inside public_html or root path of script uploaded folder/files. Please replace USERNAME with user of your web panel account who owns it.
find . -type d -exec chmod 0755 {} \;
find . -type f -exec chmod 0644 {} \;chown -R USERNAME:USERNAME *After that install or try updating and it will process. This will also fix any server related 500 / internal server error during installations too.
If it still does not work after this fix then let us know!
