Generally, this error occurs when there is an incorrect permission set for the user. We need to set the correct permission from the Plesk panel to fix it.
Below are the steps to set the correct permission from the Plesk panel
Step 1: Login into the Plesk Panel.
Step 2: Go to the left side of the screen and click on the Domains option.
Step 3: Select the domain name of which file or folder's permission you want to modify.
Step 4: Go to the File Manager and click on it.
Step 5: Select the file or folder of which permission you want to edit. Here we have selected the admin folder as an example.
Step 6: Click on the three lines icon next to the folder and click on the Change Permissions option.
Note: If a non-subscription user owns a file/directory (For example, the root or apache user), it will not be possible to modify permissions on this file/directory: the Change Permissions button will be unavailable.
Step 7: Check the box Allow inheritable permissions from the parent to propagate to this object and all child objects. Include these with entries explicitly defined here to have the file or folder inherit permissions from its parent folder (if not).
Select the check box Replace permission entries on all child objects with entries displayed here that apply to child objects if you want files and folders contained in this folder to inherit the defined folder permissions.
Select the Usernames from the Group or usernames list and permission from the Permission for section.
Step 8: Then click on the Save button to save the changes.
Step 9: Once you click on the Save button, you will get a message on the screen "File or directory access permission were successfully updated".