diff --git a/frontend/public/locales/en-GB/translation.json b/frontend/public/locales/en-GB/translation.json
index 679266b82..c30bc7c55 100644
--- a/frontend/public/locales/en-GB/translation.json
+++ b/frontend/public/locales/en-GB/translation.json
@@ -74,6 +74,8 @@
   },
   "error": {
     "pdfPassword": "The PDF Document is passworded and either the password was not provided or was incorrect",
+    "encryptedPdfMustRemovePassword": "This PDF is encrypted or password-protected. Please unlock it before converting to PDF/A.",
+    "incorrectPasswordProvided": "The PDF password is incorrect or not provided.",
     "_value": "Error",
     "dismissAllErrors": "Dismiss All Errors",
     "sorry": "Sorry for the issue!",
diff --git a/frontend/public/locales/en-US/translation.json b/frontend/public/locales/en-US/translation.json
index 68cb57546..ae23ddd73 100644
--- a/frontend/public/locales/en-US/translation.json
+++ b/frontend/public/locales/en-US/translation.json
@@ -68,6 +68,8 @@
   },
   "error": {
     "pdfPassword": "The PDF Document is passworded and either the password was not provided or was incorrect",
+    "encryptedPdfMustRemovePassword": "This PDF is encrypted or password-protected. Please unlock it before converting to PDF/A.",
+    "incorrectPasswordProvided": "The PDF password is incorrect or not provided.",
     "_value": "Error",
     "sorry": "Sorry for the issue!",
     "needHelp": "Need help / Found an issue?",
diff --git a/frontend/src/services/http.ts b/frontend/src/services/http.ts
index c8cca7930..35a79ca1e 100644
--- a/frontend/src/services/http.ts
+++ b/frontend/src/services/http.ts
@@ -1,6 +1,7 @@
 import axios from 'axios';
 import { alert } from '../components/toast';
 import { broadcastErroredFiles, extractErrorFileIds, normalizeAxiosErrorData } from './errorUtils';
+import { showSpecialErrorToast } from './specialErrorToasts';
 
 const FRIENDLY_FALLBACK = 'There was an error processing your request.';
 
@@ -49,6 +50,11 @@ function extractAxiosErrorMessage(error: any): { title: string; body: string } {
       if (typeof raw === 'string') return raw;
       try { return JSON.stringify(data); } catch { return ''; }
     })();
+    // Specific friendly mapping for encrypted PDFs (centralized toast also fires in interceptor)
+    if (ENCRYPTION_ERROR_REGEX.test(body)) {
+      const title = titleForStatus(error.response?.status);
+      return { title, body: ENCRYPTION_FRIENDLY };
+    }
     const ids = extractIds();
     const title = titleForStatus(status);
     if (ids && ids.length > 0) {
@@ -64,6 +70,9 @@ function extractAxiosErrorMessage(error: any): { title: string; body: string } {
   }
   try {
     const msg = (error?.message || String(error)) as string;
+    if (ENCRYPTION_ERROR_REGEX.test(msg)) {
+      return { title: 'Request error', body: ENCRYPTION_FRIENDLY };
+    }
     return { title: 'Network error', body: isUnhelpfulMessage(msg) ? FRIENDLY_FALLBACK : msg };
   } catch (e) {
     // ignore extraction errors
@@ -109,7 +118,17 @@ const __INTERCEPTOR_ID__ = axios.interceptors.response.use(
       }
     }
 
-    alert({ alertType: 'error', title, body, expandable: true, isPersistentPopup: false });
+    // Show specialized friendly toasts if matched; otherwise show the generic one
+    const raw = (error?.response?.data) as any;
+    let rawString: string | undefined;
+    try {
+      if (typeof raw === 'string') rawString = raw;
+      else rawString = await normalizeAxiosErrorData(raw).then((d) => (typeof d === 'string' ? d : JSON.stringify(d)));
+    } catch { /* ignore */ }
+    const handled = showSpecialErrorToast(rawString, { status });
+    if (!handled) {
+      alert({ alertType: 'error', title, body, expandable: true, isPersistentPopup: false });
+    }
     return Promise.reject(error);
   }
 );
diff --git a/frontend/src/services/specialErrorToasts.ts b/frontend/src/services/specialErrorToasts.ts
new file mode 100644
index 000000000..cdcc725fe
--- /dev/null
+++ b/frontend/src/services/specialErrorToasts.ts
@@ -0,0 +1,57 @@
+import { alert } from '../components/toast';
+
+interface ErrorToastMapping {
+  regex: RegExp;
+  i18nKey: string;
+  defaultMessage: string;
+}
+
+// Centralized list of special backend error message patterns → friendly, translated toasts
+const MAPPINGS: ErrorToastMapping[] = [
+  {
+    regex: /pdf contains an encryption dictionary/i,
+    i18nKey: 'errors.encryptedPdfMustRemovePassword',
+    defaultMessage: 'This PDF is encrypted. Please unlock it using the Unlock PDF Forms tool.'
+  },
+  {
+    regex: /the pdf document is passworded and either the password was not provided or was incorrect/i,
+    i18nKey: 'errors.incorrectPasswordProvided',
+    defaultMessage: 'The PDF password is incorrect or not provided.'
+  },
+];
+
+function titleForStatus(status?: number): string {
+  if (!status) return 'Network error';
+  if (status >= 500) return 'Server error';
+  if (status >= 400) return 'Request error';
+  return 'Request failed';
+}
+
+/**
+ * Match a raw backend error string against known patterns and show a friendly toast.
+ * Returns true if a special toast was shown, false otherwise.
+ */
+export function showSpecialErrorToast(rawError: string | undefined, options?: { status?: number }): boolean {
+  const message = (rawError || '').toString();
+  if (!message) return false;
+
+  for (const mapping of MAPPINGS) {
+    if (mapping.regex.test(message)) {
+      // Best-effort translation without hard dependency on i18n config
+      let body = mapping.defaultMessage;
+      try {
+        const anyGlobal: any = (globalThis as any);
+        const i18next = anyGlobal?.i18next;
+        if (i18next && typeof i18next.t === 'function') {
+          body = i18next.t(mapping.i18nKey, { defaultValue: mapping.defaultMessage });
+        }
+      } catch { /* ignore translation errors */ }
+      const title = titleForStatus(options?.status);
+      alert({ alertType: 'error', title, body, expandable: true, isPersistentPopup: false });
+      return true;
+    }
+  }
+  return false;
+}
+
+