If you are on the cpanel server
Run:
chown -R username:username /home/<username>/public_html
It will give the ownership to your user.
Also check the /uploads folder permission, try it with 755 then 777.
In PLESK you have to check read/write permission at
Plesk > Domains > example.com > Hosting Settings
Then grant Modify/Write permissions only to the uploads folder in PLESK:
Log into Plesk.
Go to Plesk > Domains > example.com > File Manager >wp-content ;
Click on the menu for the folder "upload" and select Change Permissions;
Select the Application pool group (IWPG_example) and add the Modify permission;
Click Ok.
Run:
chown -R username:username /home/<username>/public_html
It will give the ownership to your user.
Also check the /uploads folder permission, try it with 755 then 777.
In PLESK you have to check read/write permission at
Plesk > Domains > example.com > Hosting Settings
Then grant Modify/Write permissions only to the uploads folder in PLESK:
Log into Plesk.
Go to Plesk > Domains > example.com > File Manager >wp-content ;
Click on the menu for the folder "upload" and select Change Permissions;
Select the Application pool group (IWPG_example) and add the Modify permission;
Click Ok.