Roundcube Webmail 500 Internal Server Error

Am trying login in mine webmail via Roundcube getting this error

This page isn’t working

www.test.in is currently unable to handle this request.

HTTP ERROR 500

Are you able to access the admin page?

What does the Nginx error log say?

No sir i dont have admin page
What does it mean “Nginx error log say?”
and where should i get this

@Rahul

First attempt to load roundcube in your browser.

Then, In the terminal type

sudo tail -20 /var/log/nginx/error.log

paste the output here or PM it.

If there is no output then type this instead, and paste the output here.

sudo tail -20 /var/log/nginx/access.log

#0 /usr/local/lib/roundcubemail/program/lib/Roundcube/rcube_db.php(152): rcube_db_mysql->dsn_options(Array)
#1 /usr/local/lib/roundcubemail/program/lib/Roundcube/rcube_db.php(138): rcube_db->conn_create(Array)
#2 /usr/local/lib/roundcubemail/program/lib/Roundcube/rcube_db.php(230): rcube_db->dsn_connect(Array, 'w')
#3 /usr/local/lib/roundcubemail/program/lib/Roundcube/rcube_db.php(416): rcube_db->db_connect('w', true)
#4 /usr/local/lib/roundcubemail/program/lib/Roundcube/rcube_db.php(379): rcube_db->_query('SELECT `vars`, ...', 0, 0, Array)
#5 /usr/local/lib/roundcubemail/program/lib/Roundcube/session/db.php(106): rcube_db->query('SELECT `vars`, ...', '8alfvlna9u7e54f...')
#6 [internal function]: rcube_session_db->read('8alfvlna9u7e54f...')
#7 /usr/local/lib/roundcubemail/program/lib/Roundcube/rcube_session.php(136): session_sta" while reading response header from upstream, client: xx.xxx.xx.xxx, server: box.domain.tld, request: "GET /mail/ HTTP/2.0", upstream: "fastcgi://unix:/var/run/php/php7.2-fpm.sock:", host: "box.domain.tld"

yes admin opens but roundcube does not work

Did anyone figure this out? I recently updated my whole box (miab .5x to .6x) and had a TON of issues. I’ve finally worked them all out and all of my new box is working with the exception of Roundcube. Worst part is, it did work finally just this morning, then I went back after fixing some other stuff and it’s not working, I’m getting this 500 error no matter what I do!

UPDATE: I got it working again! Something in the Cardav plugin got broken. I disabled it and now Roundcube works again. I have not done any troubleshooting yet on Cardav though.
Roundcube has been problematic since day 1 of MiAB, isn’t there a good alternative?

Did you upgrade ubuntu or start with a fresh install? Most people that had issues either upgraded ubuntu or did not have ipv6 connectivity. Just want to exclude those from the start.