Snappdf download: Failed to open stream: Connection timed out in

I am trying to use snappdf. When trying to download, errors occur. Am I doing something wrong? Is there a solution/workaround for this?

root@invoice:/var/www/invoice/vendor/beganovich/snappdf# php snappdf download
PHP Warning:  file_get_contents( Failed to open stream: Connection timed out in /var/www/invoice/vendor/beganovich/snappdf/src/Command/DownloadChromiumCommand.php on line 70
PHP Warning:  Attempt to read property "content" on null in /var/www/invoice/vendor/beganovich/snappdf/src/Command/DownloadChromiumCommand.php on line 73
Starting download. Revision:
PHP Warning:  fopen( Failed to open stream: Connection timed out in /var/www/invoice/vendor/beganovich/snappdf/src/Command/DownloadChromiumCommand.php on line 87
Download completed. Extracting the zip archive.
Archive extracted.
PHP Warning:  chmod(): No such file or directory in /var/www/invoice/vendor/beganovich/snappdf/src/Command/DownloadChromiumCommand.php on line 105
Completed! -Linux_x64 currently in use.

Thanks for any help.
Regards, Michael

From the root of the invoice ninja project, try running this:

./vendor/bin/snappdf download --force

Thank you for your answer.

If I disable UFW on my Debian server then it works.

I have yet to figure out why the firewall is blocking this. The only thing I have configured is two ports open for incoming connections (80 and 443). As far as i know, by default, UFW is configured to deny all incoming traffic and allow all outgoing traffic.

I noticed that when I use file_get_contents, only requests with https are blocked, it works with http.

Receive data via https (not working)

php -r 'echo file_get_contents("");'

Receive data via http (works)

php -r 'echo file_get_contents("");'

I know this is off topic, but maybe it will help someone to understand who has a similar problem.