Internal Server Error fress install

I have the following problem.
After purchasing my nas I installed nextcloud.

However when opening:
192.168.1.3/nextcloud

I get the following error:
Internal Server Error

The server encountered an internal error and was unable to complete your request.
Please contact the server administrator if this error reappears multiple times, please include the technical details below in your report.
More details can be found in the server log.

The log file of nextcloud shows nothing strange about this Error. Also searched Google and forum with no results so far.

Who can help me with this problem.

Unfortunately you didn’t provide any valuable information about your environment, the NAS, the used software versions, etc., etc. so that no-one will be able to help you getting the problem solved. I definitely know that problems with NAS installations are reported regularly and therefore should be found without any difficulties.

In most cases a user hasn’t installed required php modules on the NAS.

Thanks for the quick response

My setup is:
Synology Nas ds212j
DSM nieste version
Nextcloud version 20.0.2.2
Apache 2.4
PHP 7.3
Web station
MariaDB 10

extensions:

bcmath
bz2
curl
exif
ftp
gd
gettext
iconv
intl
gmp
imagick
mailparse
mysqli
openssl
pdo_mysql
posix
soap
sockets
xmlrpc
zip

Do you need more info?