fix(connection): Detects tenant hyphen and length problems and show notification.

lang/main.json

         "gifsMenu": "GIPHY",
         "groupTitle": "Notifications",
         "hostAskedUnmute": "The moderator would like you to speak",
+        "invalidTenant": "Invalid tenant",
+        "invalidTenantHyphenDescription": "The tenant you are using is invalid (starts or ends with '-').",
+        "invalidTenantLengthDescription": "The tenant you are using is too long.",
         "invitedOneMember": "{{name}} has been invited",
         "invitedThreePlusMembers": "{{name}} and {{count}} others have been invited",
         "invitedTwoMembers": "{{first}} and {{second}} have been invited",

react/features/base/conference/middleware.any.ts

 import MiddlewareRegistry from '../redux/MiddlewareRegistry';
 import StateListenerRegistry from '../redux/StateListenerRegistry';
 import { TRACK_ADDED, TRACK_REMOVED } from '../tracks/actionTypes';
+import { parseURIString } from '../util/uri';
 
 import {
     CONFERENCE_FAILED,
     }
 
     if (error.name === JitsiConnectionErrors.CONFERENCE_REQUEST_FAILED) {
+        let notificationAction: Function = showNotification;
         const notificationProps = {
             customActionNameKey: [ 'dialog.rejoinNow' ],
             customActionHandler: [ () => dispatch(reloadNow()) ],
             descriptionKey: 'notify.connectionFailed'
         } as INotificationProps;
 
-        dispatch(showNotification(notificationProps, NOTIFICATION_TIMEOUT_TYPE.STICKY));
+        const { locationURL = { href: '' } as URL } = getState()['features/base/connection'];
+        const { tenant } = parseURIString(locationURL.href) || {};
+
+        if (tenant.startsWith('-') || tenant.endsWith('-')) {
+            notificationProps.descriptionKey = 'notify.invalidTenantHyphenDescription';
+            notificationProps.titleKey = 'notify.invalidTenant';
+            notificationAction = showErrorNotification;
+        } else if (tenant.length > 63) {
+            notificationProps.descriptionKey = 'notify.invalidTenantLengthDescription';
+            notificationProps.titleKey = 'notify.invalidTenant';
+            notificationAction = showErrorNotification;
+        }
+
+        dispatch(notificationAction(notificationProps, NOTIFICATION_TIMEOUT_TYPE.STICKY));
     }
 
     const result = next(action);