blank phpmyadmin page 500 server error - Debian 10 nginx

I'm reinstalling my server with ISPconfig and switching to Debian 10 and Nginx.
It's all gone well, except that I cannot seem to have any phpmyadmin page loading.
If I go to http://server:8081/phpmyadmin I get just a blank page. Roundcube is working fine on that port. If I make a typo, I get a page not found.
Looking at the access log, I can see:

Code:

[24/May/2020:12:21:19 +0000] "GET /phpmyadmin/ HTTP/1.1" 500 5 "-" "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:76.0) Gecko/20100101 Firefox/76.0"

So I guess there's a 500 internal server error.
Any idea where to start looking?

 

Found my problem. I had missed a semicolon at the end when adding the

Code:

$cfg['TempDir'] = '/var/lib/phpmyadmin/tmp';