# Alerts when a screen goes offline > Get a Slack, Teams, email, Telegram, PagerDuty or webhook message when a screen goes offline, comes back, or shows a blank or frozen picture. Source: https://screentinker.com/guides/digital-signage-alerts ## Alerts when a screen goes offline A screen that has gone dark doesn't tell anyone. Alerts do: when a screen has been offline for a few minutes, ScreenTinker posts a message to your team's Slack, Microsoft Teams, Telegram or PagerDuty, or sends an email. When the screen comes back, it says so. It can also tell you when a screen is on but showing a blank or frozen picture. This guide covers adding an alert channel, choosing which screens it watches, testing it, and the screen verification settings on the same page. ### Before you start - **Alerts is in Advanced view.** New accounts start in Simple view. Switch with the **Simple / Advanced** buttons at the top of the menu. - **Only a workspace Admin can add or change channels.** Everyone in the workspace can see the page. Editors and Viewers don't get the **Add alert channel**, **Send test**, **Edit** or **Delete** buttons; a note at the top says "Only a workspace admin can change this. You can look at it." See [Users and roles](https://screentinker.com/guides/digital-signage-users-roles.html). - **Have the address ready** that the messages should go to: a Slack or Teams webhook, a PagerDuty integration key, a Telegram bot, or some email addresses. The form tells you where to find each one. ### The Alerts page Choose **Alerts** in the **Automate** part of the sidebar. At the top are the **Screen verification** settings and **Recent screen problems** (see [below](#verification)). Under them is the **Add alert channel** button and your channels. Three channels: the managers' Slack hears about every screen, the kitchen's Telegram group only about the kitchen screens. Each channel card shows where it sends (the address is shortened, for example `https://hooks.slack.com/…Wy6e`), a **Sends:** line with what it sends, after how many minutes and for which screens, and when it **Last sent** a message. If the last message failed, the reason appears in amber next to it. ### Add an alert channel - Press **Add alert channel**. - **Send to**: **Slack**, **Microsoft Teams**, **Email**, **PagerDuty**, **Telegram** or **Webhook**. You can't change this later; make a new channel instead. - **Name**: anything that tells you who it reaches, such as "Café managers". - Fill in where it goes. The hint under each box says where to find it: **Slack incoming webhook**: in Slack, Apps → Incoming Webhooks → Add to a channel, then copy the webhook URL. - **Teams workflow webhook**: in Teams, the channel's ⋯ → Workflows → "Post to a channel when a webhook request is received", then copy its URL. - **Email addresses**: up to 20, separated by commas. - **PagerDuty integration key**: from a PagerDuty service, Integrations → Events API v2. - **Telegram bot token** and **Chat ID**: make a bot with @BotFather, add it to your group, and follow the hint to find the chat ID. - **Webhook URL** (and an optional **Signing secret**) if your own system should receive the alert. - **Send when**: tick the messages you want. All four are ticked on a new channel: **a screen has been offline for** 5 **minutes** (any number from 2 to 1440). - **it comes back online (after an offline alert)**. - **a screen is online but showing a problem (blank, frozen, wrong content, panel off)**. - **that screen is showing its content again**. - **For**: **All screens in this workspace** (screens you add later are included), **Screens in these groups** or **These screens**, then tick them. - Leave **On** ticked and press **Save**. A new channel. Every message type is ticked to start with. Why wait a few minutes? Screens drop off for a moment when the Wi-Fi blinks or the player restarts. Waiting 5 to 15 minutes before an alert means you only hear about screens that are really down. Each channel sends one message per outage, however long it lasts. ### Test it Press **Send test** on the channel. You see "Test message sent", and a message titled "ScreenTinker test alert" arrives where you sent it. If something is wrong, the error appears instead, for example "The service answered HTTP 404." for a mistyped webhook. A PagerDuty test opens an incident and closes it again straight away, so nobody stays paged. ### Change or switch off a channel Press **Edit**. The webhook, key or bot token is never shown again in full: its box shows only the last few characters. **Leave empty to keep the current one**, or paste a new one to replace it. Editing the kitchen's Telegram channel. The bot token stays as it is unless you type a new one. For Telegram, **Send good news silently (back online, screen OK): only problems make a sound** keeps the group's phones quiet for the good news. To pause a channel, untick **On** and save: its card is marked **Off**. **Delete** removes it for good. ### Blank, frozen or switched-off screens A screen can be online and still show nothing useful: a black picture, a picture that stopped moving, or a TV someone switched off. **Screen verification** checks the screenshots your screens send and spots these. The settings are at the top of the Alerts page: The usual settings. Only channels with the screen-problem boxes ticked get these messages. - **Ask each screen for a screenshot**: every 30 minutes to start with. Choose a different time, or "Never (only check screenshots already taken)". - **Sensitivity**: **Normal**; "Low (only when certain)" or "High (catches more, more false alarms)". - **A problem must last (minutes)**: 10 to start with. A problem shorter than this is ignored, and it clears itself when the screen recovers. - **Send alerts for**: **Blank**, **Frozen**, **Unexpected content**, **Panel off**. All but Unexpected content are ticked at first. Press **Save** after a change. Only a workspace Admin can change these; everyone else sees "Only a workspace admin can change these settings." **Recent screen problems** lists the last problems found, which screen, how long they lasted, and how they ended. A screen with a planned power-off time is not reported as switched off during it. For a message about these problems, a channel needs **a screen is online but showing a problem** ticked. The line under **Send alerts for** tells you how many of your channels have it. To check one screen by hand, see [Troubleshooting](https://screentinker.com/guides/digital-signage-troubleshooting.html). ### The owner's own email Apart from your channels, each screen's owner gets an email after a screen has been offline for 5 minutes. To stop it, they untick **Email me when devices go offline** in their **Settings**. Alert channels are for everyone else who needs to know. On a self-hosted server **Email** channels, and the owner's email, need the server's email set up (SMTP or Microsoft 365). Without it, **Send test** says "Email is not set up on this server." Webhook, Teams and Slack messages only go to public internet addresses: a webhook on your own network is refused unless the server's operator allows it (the `OUTBOUND_ALLOW_HOSTS` setting). Messages carry an "Open in ScreenTinker" link only when the server's `APP_URL` is set. ### FAQ #### A screen went offline but no alert came. Check that the channel is **On**, that the screen is covered under **For** (a group channel only covers screens in that group), and that the screen has been offline for longer than the channel's minutes. Then press **Send test**: a delivery problem shows its reason on the card. No alert goes out for a screen that has already been offline for more than a day, for example when you add the channel later. #### Why didn't I get a "back online" message? A channel only says a screen is back after it has said that screen went offline. A short drop that never reached the alert time sends neither message. #### Can different people hear about different screens? Yes. Make one channel per team and set **For** on each, for example the kitchen's Telegram group for the kitchen screens and the managers' Slack for all screens. ### Try it on your own screens Start a 14-day Pro trial on hosted ScreenTinker: up to 15 screens, every feature, no credit card. [Start your free trial](https://screentinker.com/app#/login) Or host it yourself, free and open source: [self-hosting guide](https://screentinker.com/guides/self-hosted-digital-signage.html) · [GitHub](https://github.com/screentinker/screentinker) ### Related guides - [Troubleshooting](https://screentinker.com/guides/digital-signage-troubleshooting.html) - [Groups and video walls](https://screentinker.com/guides/digital-signage-groups-video-walls.html) - [Users and roles](https://screentinker.com/guides/digital-signage-users-roles.html) - [Self-hosted digital signage](https://screentinker.com/guides/self-hosted-digital-signage.html) - [All guides](https://screentinker.com/guides/)