diff --git a/server/tests/cli/peertube.ts b/server/tests/cli/peertube.ts
index 348438533..fcf7e2e2e 100644
--- a/server/tests/cli/peertube.ts
+++ b/server/tests/cli/peertube.ts
@@ -66,6 +66,18 @@ describe('Test CLI wrapper', function () {
       await execCLI(`${env} ${cmd} auth add -u ${server.url} -U user_1 -p super_password`)
     })
 
+    it('Should not fail to add a user if there is a slash at the end of the instance URL', async function () {
+      this.timeout(60000)
+
+      const env = getEnvCli(server)
+      let fullServerURL
+      fullServerURL = server.url + '/'
+      await execCLI(`${env} ${cmd} auth add -u ${fullServerURL} -U user_1 -p super_password`)
+
+      fullServerURL = server.url + '/asdfasdf'
+      await execCLI(`${env} ${cmd} auth add -u ${fullServerURL} -U user_1 -p super_password`)
+    })
+
     it('Should default to this user', async function () {
       this.timeout(60000)
 
diff --git a/server/tools/peertube-auth.ts b/server/tools/peertube-auth.ts
index 1a4fae4ce..7673b92cd 100644
--- a/server/tools/peertube-auth.ts
+++ b/server/tools/peertube-auth.ts
@@ -80,8 +80,19 @@ program
         }
       }
     }, async (_, result) => {
+      const stripExtraneousFromPeerTubeUrl = function (url: string) {
+        // Get everything before the 3rd /.
+        const urlLength: number = url.includes('/', 8) ? url.indexOf('/', 8) : url.length
+
+        return url.substr(0, urlLength)
+      }
+
       // Check credentials
       try {
+        // Strip out everything after the domain:port.
+        // @see https://github.com/Chocobozzz/PeerTube/issues/3520
+        result.url = stripExtraneousFromPeerTubeUrl(result.url)
+
         await getAccessToken(result.url, result.username, result.password)
       } catch (err) {
         console.error(err.message)