The error “roundcube database error connection failed” indicates the MySQL password for Roudcube isn’t correct. You can usually fix this by running
/scripts/mysqlpasswd roundcube `cat /var/cpanel/roundcubepass`
however this does not always work since /var/cpanel/roundcubepass may not have the correct MySQL password for the user roundcube, the configuration file at /usr/local/cpanel/base/3rdparty/roundcube/config/db.inc.php however always has the correct password and you can use the command below to fix the issue:
/scripts/mysqlpasswd roundcube `grep mysql /usr/local/cpanel/base/3rdparty/roundcube/config/db.inc.php \
| grep -oP '(?<=roundcube:)\S*(?=@localhost)'`
If you ever see the error “libgcc_s.so.1 must be installed for pthread_cancel to work” for cPanel, this is most likely due to cPanel running out of memory.
You can check the current memory being used by running the command free -tm, you should see an output like the one below:
total used free shared buffers cached
Mem: 1850 1172 677 0 43 559
-/+ buffers/cache: 569 1280
Swap: 2047 0 2047
Total: 3898 1172 2725
To increase the memory limit for cPanel, go to Tweak Settings (in WHM) then search for “Max cPanel process memory”, you can then increase this to say 512MB from the default 256M, then click on Save.
If you get this error while creating an account in cPanel, most likely you are trying to use a package that has a dedicated IP assigned or you manually checked ‘dedicated IP’ on the account creation page while your server does not have any dedicated IPs.
To resolve this either edit the package (if the issue is with the package) under Packages >> Edit a Package in WHM or uncheck ‘dedicated IP’ option.
You can also manually edit the package file , if you have root access to the server. The file is located at /var/cpanel/packages/packagename (where packagename is the name of the package).
change this line