Paypal plugin error

By the way the site is yet not public.

Thanks for the tip but got no solution.
I did Deactivate and reactivate the plugin, then generated an entire new package for site uploading using Duplicator plugin.
What I did: removed all files from the public server under public_html not to have old stuff there.
Uploaded the site and installed it using Duplicator plugin.
Created new database
Again error persists and that is the unique problem I have after site installation and running.
The string ‘000webhost.com’ appear inserted among the email that is valid for the Paypal account, making it useless. Maybe that is something Hostinger does on purpose. But the plugin must have its own security. This show us that the account’s email address can be traced by anyone. And that would be a hazard. Or the plugin itself is acting that editing the email address with the public hostname.
Any other ideas?

Yes it does. I just found out that this will not be a real problem. I am still learning! Thanks to this event, I discovered that I can edit the entire site inside the server. So, I just edited the addresses of the plugins and the coded directly using the server environment and now made peace. Altough it actually inserts the string when you build your site on your machine and upload and install the site from scratch onto the server. Building the site directly inside the server one will not find any problem with that. So the problem was myself. Thanks for all tips.