Index: src/wp-includes/class-wp-fatal-error-handler.php
===================================================================
diff --git a/src/wp-includes/class-wp-fatal-error-handler.php b/src/wp-includes/class-wp-fatal-error-handler.php
--- a/src/wp-includes/class-wp-fatal-error-handler.php	(revision 50768)
+++ b/src/wp-includes/class-wp-fatal-error-handler.php	(date 1618756028717)
@@ -183,7 +183,11 @@
 		if ( true === $handled && wp_is_recovery_mode() ) {
 			$message = __( 'There has been a critical error on this website, putting it in recovery mode. Please check the Themes and Plugins screens for more details. If you just installed or updated a theme or plugin, check the relevant page for that first.' );
 		} elseif ( is_protected_endpoint() ) {
-			$message = __( 'There has been a critical error on this website. Please check your site admin email inbox for instructions.' );
+			if ( is_multisite() ) {
+				$message = __( 'There has been a critical error on this website. Please reach out to your site administrator, and inform them of this error for further assistance.' );
+			} else {
+				$message = __( 'There has been a critical error on this website. Please check your site admin email inbox for instructions.' );
+			}
 		} else {
 			$message = __( 'There has been a critical error on this website.' );
 		}