diff --git a/cypress/e2e/api/SessionApi.spec.js b/cypress/e2e/api/SessionApi.spec.js
index d98c81727ec..36d8f94e1e5 100644
--- a/cypress/e2e/api/SessionApi.spec.js
+++ b/cypress/e2e/api/SessionApi.spec.js
@@ -301,6 +301,19 @@ describe('The session Api', function() {
 			})
 		})
 
+		it('signals closing connection', function() {
+			cy.then(() => {
+				return new Promise((resolve, reject) => {
+					connection.close()
+					connection.push({ steps: [messages.update], version, awareness: '' })
+						.then(
+							() => reject(new Error('Push should have thrown ConnectionClosed()')),
+							resolve,
+						)
+				})
+			})
+		})
+
 		it('sends initial content if other session is alive but did not push any steps', function() {
 			let joining
 			cy.createTextSession(undefined, { filePath: '', shareToken })
diff --git a/src/services/SessionApi.js b/src/services/SessionApi.js
index 2260dd4a328..7380401c962 100644
--- a/src/services/SessionApi.js
+++ b/src/services/SessionApi.js
@@ -22,6 +22,14 @@
 import axios from '@nextcloud/axios'
 import { generateUrl } from '@nextcloud/router'
 
+export class ConnectionClosedError extends Error {
+
+	constructor(message = 'Close has already been called on the connection', ...rest) {
+		super(message, ...rest)
+	}
+
+}
+
 class SessionApi {
 
 	#options
@@ -50,6 +58,7 @@ class SessionApi {
 export class Connection {
 
 	#content
+	#closed
 	#documentState
 	#document
 	#session
@@ -66,6 +75,7 @@ export class Connection {
 		this.#content = content
 		this.#documentState = documentState
 		this.#options = options
+		this.closed = false
 	}
 
 	get session() {
@@ -99,7 +109,7 @@ export class Connection {
 	}
 
 	sync({ version }) {
-		return axios.post(this.#url('session/sync'), {
+		return this.#post(this.#url('session/sync'), {
 			...this.#defaultParams,
 			filePath: this.#options.filePath,
 			version,
@@ -107,7 +117,7 @@ export class Connection {
 	}
 
 	save({ version, autosaveContent, documentState, force, manualSave }) {
-		return axios.post(this.#url('session/save'), {
+		return this.#post(this.#url('session/save'), {
 			...this.#defaultParams,
 			filePath: this.#options.filePath,
 			version,
@@ -119,7 +129,7 @@ export class Connection {
 	}
 
 	push({ steps, version, awareness }) {
-		return axios.post(this.#url('session/push'), {
+		return this.#post(this.#url('session/push'), {
 			...this.#defaultParams,
 			filePath: this.#options.filePath,
 			steps,
@@ -130,7 +140,7 @@ export class Connection {
 
 	// TODO: maybe return a new connection here so connections have immutable state
 	update(guestName) {
-		return axios.post(this.#url('session'), {
+		return this.#post(this.#url('session'), {
 			...this.#defaultParams,
 			guestName,
 		}).then(({ data }) => {
@@ -146,7 +156,7 @@ export class Connection {
 			+ '&sessionId=' + encodeURIComponent(this.#session.id)
 			+ '&sessionToken=' + encodeURIComponent(this.#session.token)
 			+ '&shareToken=' + encodeURIComponent(this.#options.shareToken || '')
-		return axios.post(url, formData, {
+		return this.#post(url, formData, {
 			headers: {
 				'Content-Type': 'multipart/form-data',
 			},
@@ -154,7 +164,7 @@ export class Connection {
 	}
 
 	insertAttachmentFile(filePath) {
-		return axios.post(_endpointUrl('attachment/filepath'), {
+		return this.#post(_endpointUrl('attachment/filepath'), {
 			documentId: this.#document.id,
 			sessionId: this.#session.id,
 			sessionToken: this.#session.token,
@@ -163,7 +173,16 @@ export class Connection {
 	}
 
 	close() {
-		return axios.post(this.#url('session/close'), this.#defaultParams)
+		const promise = this.#post(this.#url('session/close'), this.#defaultParams)
+		this.closed = true
+		return promise
+	}
+
+	#post(...args) {
+		if (this.closed) {
+			return Promise.reject(new ConnectionClosedError())
+		}
+		return axios.post(...args)
 	}
 
 	#url(endpoint) {