My encoder doesn't send the encoded video to main website. I checked the log configuration:
[07-Apr-2019 12:20:27 America/New_York] downloadFile: downloadedFile = /var/www/html/tube-encoder/videos/original_05WSAIdentities_YPTuniqid_5caa23480acca9.64916047 | url = http://10.26.20.180/tube-encoder/videos/original_05WSAIdentities_YPTuniqid_5caa23480acca9.64916047
[07-Apr-2019 12:20:27 America/New_York] PHP Fatal error: Uncaught Error: Call to undefined function utf8_encode() in /var/www/html/tube-encoder/objects/Encoder.php:385
Stack trace:
thrown in /var/www/html/tube-encoder/objects/Encoder.php on line 385
[07-Apr-2019 12:20:32 America/New_York] PHP Fatal error: Uncaught Error: Call to undefined function utf8_decode() in /var/www/html/tube-encoder/objects/functions.php:60
Stack trace:
thrown in /var/www/html/tube-encoder/objects/functions.php on line 60
The status of encoder is downloading.... . Any idea how can I resolve the issue?

you need to fix this: PHP Fatal error: Uncaught Error: Call to undefined function utf8_encode
try to google for a solution
This can be fixed in by running the following.
sudo apt-get install php-xml
@DanielnetoDotCom This should be added to the install documents
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Most helpful comment
This can be fixed in by running the following.
sudo apt-get install php-xml@DanielnetoDotCom This should be added to the install documents