diff --git a/packages/backend/src/remote/resolve-user.ts b/packages/backend/src/remote/resolve-user.ts
index 94f27977f..9206dc6bd 100644
--- a/packages/backend/src/remote/resolve-user.ts
+++ b/packages/backend/src/remote/resolve-user.ts
@@ -18,7 +18,8 @@ const mentionUriCache = new Cache<string>("resolveMentionUserUri", 60 * 60 * 72)
 export async function resolveUser(
 	username: string,
 	host: string | null,
-	refresh: boolean = true
+	refresh: boolean = true,
+	awaitRefresh: boolean = true
 ): Promise<User> {
 	const usernameLower = username.toLowerCase();
 
@@ -104,7 +105,7 @@ export async function resolveUser(
 
 	// If user information is out of date, return it by starting over from WebFinger
 	if (
-		refresh && (
+		refresh && awaitRefresh && (
 			user.lastFetchedAt == null ||
 			Date.now() - user.lastFetchedAt.getTime() > 1000 * 60 * 60 * 24
 		)
@@ -172,6 +173,10 @@ export async function resolveUser(
 				return u;
 			}
 		});
+	} else if (refresh && !awaitRefresh && (user.lastFetchedAt == null || Date.now() - user.lastFetchedAt.getTime() > 1000 * 60 * 60 * 24)) {
+		// Run the refresh in the background
+		// noinspection ES6MissingAwait
+		resolveUser(username, host, true, true);
 	}
 
 	logger.info(`return existing remote user: ${acctLower}`);
diff --git a/packages/backend/src/server/api/mastodon/helpers/user.ts b/packages/backend/src/server/api/mastodon/helpers/user.ts
index 4a000e405..15b664daf 100644
--- a/packages/backend/src/server/api/mastodon/helpers/user.ts
+++ b/packages/backend/src/server/api/mastodon/helpers/user.ts
@@ -41,6 +41,7 @@ import { UserProfile } from "@/models/entities/user-profile.js";
 import { verifyLink } from "@/services/fetch-rel-me.js";
 import { MastoApiError } from "@/server/api/mastodon/middleware/catch-errors.js";
 import { MastoContext } from "@/server/api/mastodon/index.js";
+import { resolveUser } from "@/remote/resolve-user.js";
 
 export type AccountCache = {
     locks: AsyncLock;
@@ -233,9 +234,13 @@ export class UserHelpers {
     public static async getUserFromAcct(acct: string): Promise<User> {
         const split = acct.toLowerCase().split('@');
         if (split.length > 2) throw new Error('Invalid acct');
-        return Users.findOneBy({ usernameLower: split[0], host: split[1] ?? IsNull() })
-            .then(p => {
-                if (p) return p;
+        return split[1] == null
+            ? Users.findOneBy({ usernameLower: split[0], host: split[1] ?? IsNull() })
+                .then(p => {
+                    if (p) return p;
+                    throw new MastoApiError(404);
+                })
+            : resolveUser(split[0], split[1], true, false).catch(() => {
                 throw new MastoApiError(404);
             });
     }