FTP access from wordpress after PHP upgrade

I just installed PHP 7.3

Between the PHP alternatives, I have theese options:

#~ sudo update-alternatives --config php
There are 2 choices for the alternative php (providing /usr/bin/php).
  Selection    Path             Priority   Status
------------------------------------------------------------
* 0            /usr/bin/php7.3   73        auto mode
  1            /usr/bin/php7.0   70        manual mode
  2            /usr/bin/php7.3   73        manual mode
Press <enter> to keep the current choice[*], or type selection number:

I have this default PHP option:

~# php -v
PHP 7.3.15-3+ubuntu18.04.1+deb.sury.org+1 (cli) (built: Feb 23 2020 07:23:33) ( NTS )
Copyright (c) 1997-2018 The PHP Group
Zend Engine v3.3.15, Copyright (c) 1998-2018 Zend Technologies
    with Zend OPcache v7.3.15-3+ubuntu18.04.1+deb.sury.org+1, Copyright (c) 1999-2018, by Zend Technologies

I was told I have to change the PHP version in each site I have.
In the ´/etc/nginx/sites-enabled´ folder I changed fastcgi_pass unix:/var/run/php/php7.0-fpm.sock; for fastcgi_pass unix:/var/run/php/php7.3-fpm.sock;

That's what I have now:

location ~ \.php$ {
        #try_files $uri /index.php;
        #include fastcgi_params;
        #fastcgi_pass unix:/var/run/php5-fpm.sock;
        include snippets/fastcgi-php.conf;
        fastcgi_pass unix:/var/run/php/php7.3-fpm.sock;
        fastcgi_cache_bypass $skip_cache;
        fastcgi_no_cache $skip_cache;
        fastcgi_cache WORDPRESS;
        fastcgi_cache_valid  60m;
        fastcgi_buffers 16 16k;
        fastcgi_buffer_size 32k;
        #fastcgi_read_timeout 60s;
    }

You can check that here: https://premios.acdm.club/info.php

But when I try to update my plugins on my wordpress it shows me an error FTP connection. I can access without a problem with mu FTP client. It seems something related with permissions.

I can update with fastcgi_pass unix:/var/run/php/php7.0-fpm.sock; bu no with fastcgi_pass unix:/var/run/php/php7.3-fpm.sock;

What do I need to update to make updating work.