What is your web server user? What is the user you run the Friendica worker cron job with? Both should be the same and neither should be root.

@8Petros. (Fediverse > Mastodon®) @Hypolite Petovan The storage folder should be accessible and writeable by your webserver user. On debian, that is "www-data".
If you are running the worker with the cronjob, make sure that is running as the same user. Also if you are using systemd service, check the service file and make sure it's using the same user.

A blank screen in browser usually is caused by fatal php errors. You can check your webserver logs and see if they have been logged somewere,
or you can add in index.php, just after the line use Dice\Dice; this code:

ini_set('log_errors', 1);
ini_set('error_reporting', E_WARNING | E_ERROR | E_PARSE | E_NOTICE);
ini_set('error_log', '/tmp/php.log');

and try again. errors should be then be written to /tmp/php.log

the error "ne:ERR_HTTP_RESPONSE_CODE_FAILURE" is an android thing.

@Fabio -- kudos!

Thanks to you, I learned today how to:

1. From my cron table retrieve the username: friendica

2. From /var/www/friendica find out out ownership and mode: friendica:www-data 0750

3. In /var/www/friendica create log/friendica.log

4. Apply details from #2 to the directory I created for media files

And now the storage switch went without any glitches.

root@tepewu:/home/yunohost.multimedia/petroskowo# ls
0c  2a  37  41  4d  61  71  8c  bf  d5  f6
0e  2e  3a  42  57  62  73  93  c8  e3  ff
29  33  3e  4b  60  6d  79  94  c9  e9  index.html

Thank you for your support.