diff --git a/app/src/main/java/com/keylesspalace/tusky/ComposeActivity.java b/app/src/main/java/com/keylesspalace/tusky/ComposeActivity.java
index 2c459fd81..5b53b0e66 100644
--- a/app/src/main/java/com/keylesspalace/tusky/ComposeActivity.java
+++ b/app/src/main/java/com/keylesspalace/tusky/ComposeActivity.java
@@ -314,6 +314,7 @@ public final class ComposeActivity
                             activeAccount.getFullName()));
 
             mastodonApi.getInstance()
+                    .observeOn(AndroidSchedulers.mainThread())
                     .as(autoDisposable(from(this, Lifecycle.Event.ON_DESTROY)))
                     .subscribe(this::onFetchInstanceSuccess, this::onFetchInstanceFailure);