diff --git a/changelog/unreleased/issue-19012.toml b/changelog/unreleased/issue-19012.toml
new file mode 100644
index 000000000000..00cd844e8119
--- /dev/null
+++ b/changelog/unreleased/issue-19012.toml
@@ -0,0 +1,5 @@
+type = "fixed"
+message = "Fixing 'unknown format' error on sidecar overview page."
+
+issues = ["19012"]
+pulls = ["19128"]
diff --git a/graylog2-web-interface/src/components/sidecars/sidecars/SidecarRow.jsx b/graylog2-web-interface/src/components/sidecars/sidecars/SidecarRow.jsx
index 4d5eb757ad73..16c7db76ddcf 100644
--- a/graylog2-web-interface/src/components/sidecars/sidecars/SidecarRow.jsx
+++ b/graylog2-web-interface/src/components/sidecars/sidecars/SidecarRow.jsx
@@ -30,13 +30,9 @@ import recentMessagesTimeRange from 'util/TimeRangeHelper';
 import style from './SidecarRow.css';
 
 const SidecarTR = styled.tr(({ inactive, theme }) => css`
-  color: ${inactive ? theme.utils.contrastingColor(theme.colors.table.background, 'AA') : 'currentColor'};
+  color: ${inactive ? theme.utils.contrastingColor(theme.colors.global.contentBackground, 'AA') : 'currentColor'};
   opacity: ${inactive ? 0.9 : 1};
 
-  &:nth-of-type(2n+1) {
-    color: ${inactive ? theme.utils.contrastingColor(theme.colors.table.backgroundAlt, 'AA') : 'currentColor'};
-  }
-
   td:not(:last-child) {
     font-style: ${inactive ? 'italic' : 'normal'};
   }