diff --git a/about.pl b/about.pl
index fc8dcec21c..62a94d87f4 100755
--- a/about.pl
+++ b/about.pl
@@ -217,7 +217,10 @@ if (    C4::Context->config('zebra_auth_index_mode')
     push @xml_config_warnings, { error => 'zebra_auth_index_mode_is_grs1' };
 }
 
-if ( (C4::Context->config('zebra_auth_index_mode') eq 'dom') && ($context->{'server'}->{'authorityserver'}->{'config'} !~ /zebra-authorities-dom.cfg/) ) {
+if( (   C4::Context->config('zebra_auth_index_mode')
+    and C4::Context->config('zebra_auth_index_mode') eq 'dom' )
+    && ( $context->{'server'}->{'authorityserver'}->{'config'} !~ /zebra-authorities-dom.cfg/ ) )
+{
     push @xml_config_warnings, {
         error => 'zebra_auth_index_mode_mismatch_warn'
     };