diff --git a/src/connectors/captcha.ts b/src/connectors/captcha.ts
index e66d6b07ad5..f42ff36fcbc 100644
--- a/src/connectors/captcha.ts
+++ b/src/connectors/captcha.ts
@@ -47,7 +47,7 @@ async function start() {
 
   let decodedData: any;
   try {
-    decodedData = JSON.parse(b64Decode(data));
+    decodedData = JSON.parse(b64Decode(data, true));
   } catch (e) {
     error("Cannot parse data.");
     return;
diff --git a/src/connectors/common.ts b/src/connectors/common.ts
index 508fed5f43d..4801cf60af8 100644
--- a/src/connectors/common.ts
+++ b/src/connectors/common.ts
@@ -14,7 +14,11 @@ export function getQsParam(name: string) {
   return decodeURIComponent(results[2].replace(/\+/g, " "));
 }
 
-export function b64Decode(str: string) {
+export function b64Decode(str: string, spaceAsPlus = false) {
+  if (spaceAsPlus) {
+    str = str.replace(/ /g, "+");
+  }
+
   return decodeURIComponent(
     Array.prototype.map
       .call(atob(str), (c: string) => {