diff --git a/src/components/NewMessageModal.vue b/src/components/NewMessageModal.vue
index 41f7d30daf..faa1d3362f 100644
--- a/src/components/NewMessageModal.vue
+++ b/src/components/NewMessageModal.vue
@@ -27,7 +27,7 @@ import logger from '../logger'
 import { toPlain } from '../util/text'
 import { saveDraft } from '../service/MessageService'
 import Composer from './Composer'
-import { showError, showSuccess, showUndo } from '@nextcloud/dialogs'
+import { showError, showSuccess } from '@nextcloud/dialogs'
 import { translate as t } from '@nextcloud/l10n'
 import { UNDO_DELAY } from '../store/constants'
 
@@ -127,46 +127,20 @@ export default {
 				dataForServer.sendAt = Math.floor((now + UNDO_DELAY) / 1000)
 			}
 
-			let message
 			if (!this.composerData.id) {
-				message = await this.$store.dispatch('outbox/enqueueMessage', {
+				await this.$store.dispatch('outbox/enqueueMessage', {
 					message: dataForServer,
 				})
 			} else {
-				message = await this.$store.dispatch('outbox/updateMessage', {
+				await this.$store.dispatch('outbox/updateMessage', {
 					message: dataForServer,
 					id: this.composerData.id,
 				})
 			}
 
 			if (!data.sendAt || data.sendAt < Math.floor((now + UNDO_DELAY) / 1000)) {
-				showUndo(
-					t('mail', 'Message sent'),
-					async() => {
-						logger.info('Attempting to stop sending message ' + message.id)
-						const stopped = await this.$store.dispatch('outbox/stopMessage', { message })
-						logger.info('Message ' + message.id + ' stopped', { message: stopped })
-						await this.$store.dispatch('showMessageComposer', {
-							type: 'outbox',
-							data: {
-								...message, // For id and other properties
-								...data, // For the correct body values
-							},
-						})
-					}, {
-						timeout: UNDO_DELAY,
-						close: true,
-					}
-				)
-
-				setTimeout(() => {
-					try {
-						this.$store.dispatch('outbox/sendMessage', { id: message.id })
-					} catch (error) {
-						showError(t('mail', 'Could not send message'))
-						logger.error('Could not delay-send message ' + message.id, { message })
-					}
-				}, UNDO_DELAY)
+				// Awaiting here would keep the modal open for a long time and thus block the user
+				this.$store.dispatch('outbox/sendMessageWithUndo', { id: this.composerData.id })
 			}
 			if (data.draftId) {
 				// Remove old draft envelope
diff --git a/src/components/OutboxMessageListItem.vue b/src/components/OutboxMessageListItem.vue
index 35793bcb04..69520eb7d8 100644
--- a/src/components/OutboxMessageListItem.vue
+++ b/src/components/OutboxMessageListItem.vue
@@ -40,7 +40,7 @@
 			<ActionButton
 				icon="icon-checkmark"
 				:close-after-click="true"
-				@click="sendMessage">
+				@click="sendMessageNow">
 				{{ t('mail', 'Send now') }}
 				<template #icon>
 					<Send
@@ -71,6 +71,7 @@ import { showError, showSuccess } from '@nextcloud/dialogs'
 import { matchError } from '../errors/match'
 import { html, plain } from '../util/text'
 import Send from 'vue-material-design-icons/Send'
+import { UNDO_DELAY } from '../store/constants'
 
 export default {
 	name: 'OutboxMessageListItem',
@@ -128,14 +129,13 @@ export default {
 				}))
 			}
 		},
-		async sendMessage(data) {
-			logger.debug('sending message', { data })
-			try {
-				await this.$store.dispatch('outbox/sendMessage', { id: this.message.id, force: true })
-				showSuccess(t('mail', 'Message sent'))
-			} catch (error) {
-				showError(t('mail', 'Could not send message'))
+		async sendMessageNow() {
+			const message = {
+				...this.message,
+				sendAt: (new Date().getTime() + UNDO_DELAY) / 1000,
 			}
+			await this.$store.dispatch('outbox/updateMessage', { message, id: message.id })
+			await this.$store.dispatch('outbox/sendMessageWithUndo', { id: message.id })
 		},
 		async openModal() {
 			await this.$store.dispatch('showMessageComposer', {
diff --git a/src/store/outbox/actions.js b/src/store/outbox/actions.js
index 397de6d0be..ccfd58604c 100644
--- a/src/store/outbox/actions.js
+++ b/src/store/outbox/actions.js
@@ -22,7 +22,10 @@
 
 import * as OutboxService from '../../service/OutboxService'
 import logger from '../../logger'
+import { showError, showUndo } from '@nextcloud/dialogs'
+import { translate as t } from '@nextcloud/l10n'
 import { UNDO_DELAY } from '../constants'
+import { html, plain } from '../../util/text'
 
 export default {
 	async fetchMessages({ getters, commit }) {
@@ -87,18 +90,29 @@ export default {
 		return updatedMessage
 	},
 
+	/**
+	 * Send an outbox message right now.
+	 *
+	 * @param {object} store Vuex destructuring object
+	 * @param {function} store.commit Vuex commit object
+	 * @param {object} store.getters Vuex getters object
+	 * @param {object} data Action data
+	 * @param {number} data.id Id of outbox message to send
+	 * @param {boolean} data.force Force sending a message even if it has no sendAt timestamp
+	 * @returns {Promise<boolean>} Resolves to false if sending was skipped
+	 */
 	async sendMessage({ commit, getters }, { id, force = false }) {
 		// Skip if the message has been deleted/undone in the meantime
 		const message = getters.getMessage(id)
 		logger.debug('Sending message ' + id, { message, force })
 		if (!force && (!message || !message.sendAt)) {
 			logger.debug('Skipped sending message that was undone')
-			return
+			return false
 		}
 
 		if (message.sendAt * 1000 > new Date().getTime() + UNDO_DELAY) {
 			logger.debug('Skipped sending message that is scheduled for the future')
-			return
+			return false
 		}
 
 		try {
@@ -110,5 +124,53 @@ export default {
 		}
 
 		commit('deleteMessage', { id })
+		return true
+	},
+
+	/**
+	 * Wait for UNDO_DELAY before sending the message and show a toast with an undo action.
+	 *
+	 * @param {object} store Vuex destructuring object
+	 * @param {function} store.dispatch Vuex dispatch object
+	 * @param {object} store.getters Vuex getters object
+	 * @param {object} data Action data
+	 * @param {number} data.id Id of outbox message to send
+	 * @returns {Promise<boolean>} Resolves to false if sending was skipped. Resolves after UNDO_DELAY has elapsed and the message dispatch was triggered. Warning: This might take a long time, depending on UNDO_DELAY.
+	 */
+	async sendMessageWithUndo({ getters, dispatch }, { id }) {
+		return new Promise((resolve, reject) => {
+			const message = getters.getMessage(id)
+
+			showUndo(
+				t('mail', 'Message sent'),
+				async() => {
+					logger.info('Attempting to stop sending message ' + message.id)
+					const stopped = await dispatch('stopMessage', { message })
+					logger.info('Message ' + message.id + ' stopped', { message: stopped })
+					await dispatch('showMessageComposer', {
+						type: 'outbox',
+						data: {
+							...message,
+							// The composer expects rich body data and not just a string
+							body: message.isHtml ? html(message.body) : plain(message.body),
+						},
+					}, { root: true })
+				}, {
+					timeout: UNDO_DELAY,
+					close: true,
+				}
+			)
+
+			setTimeout(async() => {
+				try {
+					const wasSent = await dispatch('sendMessage', { id: message.id })
+					resolve(wasSent)
+				} catch (error) {
+					showError(t('mail', 'Could not send message'))
+					logger.error('Could not delay-send message ' + message.id, { message })
+					reject(error)
+				}
+			}, UNDO_DELAY)
+		})
 	},
 }