# How login protection works

> On one IP, each platform allows only one login. Signing in as a different account in the store window is blocked.

Source: https://merca.getchrovia.com/en/docs/login-protection

Don't sign in to different store accounts on the same platform through the same IP. Merca records the login at launch, and checks again in the store window. Add the username when you [add a store](https://merca.getchrovia.com/en/docs/add-store), and pick a node when you [add a node](https://merca.getchrovia.com/en/docs/import-node). Both checks run in the desktop app.

## Only one login per platform on an IP

After you check a node, it has an IP. The first time you **Launch** a store on that IP, Merca records the platform and username under **Account records**, marked **Allowed**.

![Allowed in account records](https://merca.getchrovia.com/docs/screenshots/login-protection-approved.webp)

If you then launch another store on the same IP, same platform, but a different username, launch is blocked: **Another account already uses this platform on this node.** The store window does not open.

![Launch blocked](https://merca.getchrovia.com/docs/screenshots/login-protection-launch-blocked.webp)

That username is added to **Account records** as **Blocked**. Launching it again is still blocked until you **Allow** it. The **Allowed** login can still launch.

**Add store** does not run this check. **Launch** does. The store needs a node first.

The same IP can serve different platforms. Amazon on one login and Shopee on another is fine. What gets blocked is two logins on the same platform. One Amazon, one TikTok Shop, and one Walmart on the same node is also fine; see [Can one node run stores on different platforms](https://merca.getchrovia.com/en/docs/node-platforms).

Account records are keyed by IP and are kept for good. If two nodes share an IP, they share the records.

If another Merca user later buys that IP and you still have an **Allowed** record, their launch of a different account on the same platform is blocked, and they cannot **Allow** a new record. After you delete the Allowed record, other accounts can launch; their own **Blocked** row still stops that login until they Allow it. The **Deleted** row stays in the list so later users can see this IP was used.

### If launch is blocked

1. Open the Merca desktop app and go to **Nodes**.
2. Open **Account records** on that node.
3. If this login should use that IP (for example a platform sub-account), click **Allow**. If the list already has someone else's **Allowed** record that was not deleted, **Allow** is not available. If an account should no longer use the IP, **Delete** its record. To allow a sub-account, see [How to add a platform sub-account](https://merca.getchrovia.com/en/docs/platform-subaccount).

![Blocked in account records](https://merca.getchrovia.com/docs/screenshots/login-protection-blocked.webp)

After **Allow**, this login can use the IP; the **Allowed** login still can. **Delete** keeps the row in the list as **Deleted**. It cannot be undone, and it no longer takes part in launch checks. Launching the same username again adds a new **Allowed** row. Allow and delete need the owner or an admin.

## The store window checks the login

In the store browser, signing in with a username that is not the one saved on the store is blocked. The alert is **Login does not match**.

![Login does not match](https://merca.getchrovia.com/docs/screenshots/login-protection-mismatch.webp)

Close the alert and sign in with the saved username. To use a different account, change the store **Username** in Merca, then launch again.

Signing in to a platform this store is not set up for is also blocked: **Platform not on this store**.

![Platform not on this store](https://merca.getchrovia.com/docs/screenshots/login-protection-unbound.webp)