[Koha] Software error

[Nasiru Yakubu]

Hi,

We have noticed the error below at our library and we really need
assistance to resolve the issue.

We are running Koha 3 on Ubuntu on a virtual server.

Please let me know if there is any other information required in order to
assists us further issue.
Software error:

Can't call method "do" on unblessed reference at
/usr/share/koha/lib/C4/Context.pm line 816.
BEGIN failed--compilation aborted at /usr/share/koha/lib/C4/Auth.pm line 88.
Compilation failed in require at
/usr/share/koha/opac/cgi-bin/opac/opac-main.pl line 23.
BEGIN failed--compilation aborted at
/usr/share/koha/opac/cgi-bin/opac/opac-main.pl line 23.

For help, please send mail to the webmaster ([no address given]), giving
this error message and the time and date of the error.