Timezone ID 'UTC' is invald - after Installation

New installation with latest version (19.0.2)
OS: Ubuntu 20.04.1
nginx: 1.19.2
php: 7.4
Database: MariaDB server 10.5.5

The server response with an internal error and the error log of nginx says:

2020/09/03 22:31:09 [error] 6250#6250: *54 FastCGI sent in stderr: “PHP message: PHP Notice: date_default_timezone_set(): Timezone ID ‘UTC’ is invalid in /var/www/utuf_nextcloud/lib/base.php on line 613PHP message: {“reqId”:“iYTzuO7YTCqhAy8Bv5tb”,“level”:3,“time”:“2020-09-03T20:31:09+00:00”,“remoteAddr”:“xx.x.xxx.xxx”,“user”:”–",“app”:“index”,“method”:“GET”,“url”:"/",“message”:{“Exception”:“RuntimeException”,“Message”:“Could not set timezone to UTC”,“Code”:0,“Trace”:[{“file”:"/var/www/utuf_nextcloud/lib/base.php",“line”:1095,“function”:“init”,“class”:“OC”,“type”:"::"},{“file”:"/var/www/utuf_nextcloud/index.php",“line”:35,“args”:["/var/www/utuf_nextcloud/lib/base.php"],“function”:“require_once”}],“File”:"/var/www/utuf_nextcloud/lib/base.php",“Line”:614,“CustomMessage”:"–"},“userAgent”:“Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_6) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/13.1.2 Safari/605.1.15”,“version”:""}" while reading response header from upstream, client: xx.x.xxx.xxx, server: cloud.utuf.ch, request: “GET / HTTP/2.0”, upstream: “fastcgi://unix:/run/php/php7.4-fpm.sock:”, host: “cloud.utuf.ch”

If I change /etc/php/7.4/fpm/pool.d/www.conf-file:
variable: catch_workers_output = yes, the error changes:

2020/09/03 22:22:28 [error] 6250#6250: *48 FastCGI sent in stderr: “PHP message: PHP Notice: date_default_timezone_set(): Timezone ID ‘UTC’ is invalid in /var/www/utuf_nextcloud/lib/base.php on line 613PHP message: PHP Fatal error: DateTime::createFromFormat(): Timezone database is corrupt - this should never happen! in /var/www/utuf_nextcloud/lib/private/Log/LogDetails.php on line 48” while reading response header from upstream, client: xx.x.xxx.xxx, server: cloud.utuf.ch, request: “GET / HTTP/2.0”, upstream: “fastcgi://unix:/run/php/php7.4-fpm.sock:”, host: “cloud.utuf.ch”

Can anyone help me with this?

Check your timezone entry in php.ini file

Command php - i can help to find the ini file.

Nothing. I changed the variable in php.ini the directories /etc/php/7.4/cli and /etc/php/7.4/fpm and restarted with systemctl restart php7.4-fpm

Still getting the same error…

2020/09/04 08:22:18 [error] 43545#43545: *11 FastCGI sent in stderr: “PHP message: PHP Notice: date_default_timezone_set(): Timezone ID ‘UTC’ is invalid in /var/www/utuf_nextcloud/lib/base.php on line 613PHP message: {“reqId”:“saCvwbROecprVSID5PHJ”,“level”:3,“time”:“2020-09-04T06:22:18+00:00”,“remoteAddr”:“xx.x.xxx.xxx”,“user”:”–",“app”:“index”,“method”:“GET”,“url”:"/",“message”:{“Exception”:“RuntimeException”,“Message”:“Could not set timezone to UTC”,“Code”:0,“Trace”:[{“file”:"/var/www/utuf_nextcloud/lib/base.php",“line”:1095,“function”:“init”,“class”:“OC”,“type”:"::"},{“file”:"/var/www/utuf_nextcloud/index.php",“line”:35,“args”:["/var/www/utuf_nextcloud/lib/base.php"],“function”:“require_once”}],“File”:"/var/www/utuf_nextcloud/lib/base.php",“Line”:614,“CustomMessage”:"–"},“userAgent”:“Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_6) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/13.1.2 Safari/605.1.15”,“version”:""}" while reading response header from upstream, client: xx.x.xxx.xxx, server: cloud.utuf.ch, request: “GET / HTTP/2.0”, upstream: “fastcgi://unix:/run/php/php7.4-fpm.sock:”, host: “cloud.utuf.ch”

Where does it try to set the timezone???