# Connect your ERP Connecting Business Central or SAP S/4HANA, the sign-in routes each offers, and what you can do once connected Section: app. Audience: public. Updated: 2026-10-10. --- ERP connections live under **"ERP"**, in **"Settings"**. Until September 2026 this was a page of its own in the sidebar; an old link to it opens the section. Two systems are supported: Microsoft Dynamics 365 Business Central and **"SAP S/4HANA"**. Credentials you give here are held by the platform on the server side, not in your browser. Each system has its own card, laid out like the store cards in **"Stores"**, and every action is on its card. A system you have not connected shows its connect buttons; a connected one shows its name, its state and what you can do with it. ## Business Central The **"Business Central"** card offers two routes. **"Connect with Microsoft"** signs you in through Microsoft. Depending on your tenant, an administrator may have to grant consent first. If that happens you are sent to Microsoft, and when you come back the app picks the result up and returns you to **"ERP"** in **"Settings"** with the finishing dialog open. You do not have to navigate back yourself. **"Connect manually"** takes the credentials directly, for tenants where the Microsoft route is not available. Give the connection a name in **"Connection name"** so several environments stay apart. A sandbox and a production tenant look alike in a list otherwise. To connect another environment, use **"Add another"** at the foot of a connected card; it offers the same routes. ## SAP S/4HANA **"Connect SAP"** opens a dialog headed **"Connect SAP S/4HANA"** with three ways in: **"SAP sandbox (API key)"** for trying it out, **"My SAP tenant (OAuth 2.0)"**, and **"My SAP tenant (communication user)"**. Pick the one your SAP administrator tells you to. They differ in how SAP authenticates us, not in what Horizon then does. Certificate-based sign-in is not offered. Only the account owner or an Admin can connect, test or disconnect an SAP system, or change what Horizon reads from it. Every other team member sees the connections and what Horizon reads from them, and can browse their data. The merchant guide, with what to ask your SAP administrator and what each error means, is [Connect SAP S/4HANA](/app/connect-sap/). ## Once connected **"Browse data"** gives you a read-only view of the connected system. Horizon reads; it does not write back. For SAP this covers fifteen objects, from business partners and products to sales orders, purchase orders, material stock and outbound deliveries. Nothing you browse is stored. An SAP card also has a **"What Horizon reads from SAP"** panel with three switches, all off until the owner or an Admin turns them on. **"Stock levels"** copies each SAP plant's stock into its own SAP location. **"Sales orders (reference copy)"** keeps a read-only copy of the sales orders created in a set period (by default the 90 days before the first run) and follows their changes. **"Outbound deliveries (reference copy)"** keeps a read-only copy of outbound deliveries. Only stock is used by Horizon: the two copies are for reference, no screen lists them yet, and none of the three creates orders, shipments, tracking or products, or writes to SAP. Each switch shows a progress line: up to date, catching up (the next run continues where the last one stopped), or stuck. Stuck means Horizon cannot get further on its own, and the line asks you to contact support. The details are in [Connect SAP S/4HANA](/app/connect-sap/#what-horizon-reads-from-sap). The rest of this section is Business Central only. An SAP card still has no catalogue import and no item matching: stock is matched to products only by an exact SKU. Product passports can instead be filled from SAP's product master by a separate nightly sync, which our team sets up. On a Business Central card you can bring the item catalogue across as Horizon products. Turn on **"Create products from items"**, then use **"Import as products"** to preview what would happen before committing, and **"Create products"** to do it. The preview is worth reading. It separates new products to create from items it would link to products you already have, by SKU or by GTIN, and it tells you what it is skipping and why: service and non-stock items, items blocked in the source system, and duplicates that need a human decision. An import run without reading the preview is how a catalogue acquires duplicates. ## What your plan controls ERP connections are not on every plan. When yours does not include them, the app says so and offers the upgrade route rather than presenting a form that would fail. Access is enforced by the platform, not just hidden. ## Disconnecting **"Disconnect"** removes the connection, with a confirmation first. For SAP the stored credential is deleted too; nothing in your SAP system changes. If the credential cannot be deleted, the SAP connection is kept, its card shows **"Error"** with **"We could not delete the stored credential just now, so this connection is kept. Nothing was changed in SAP. Try disconnecting again later, and contact support if it keeps happening."**, and Horizon stops reading from it. **Support:** write to support@horizonlogistics.eu.