diff --git a/main.lua b/main.lua
index 6591c13..b4f6d07 100644
--- a/main.lua
+++ b/main.lua
@@ -1186,17 +1186,36 @@ function Bookhoard:_linkBookThenPull(interactive)
             end
 
             if result and result.status == 404 then
-                -- Genuinely unknown to the server (sideloaded book). The
-                -- legacy push-bootstrap only ever linked such books via fuzzy
-                -- title/author matching; keep that as a background attempt,
-                -- but tell interactive users to push explicitly.
-                if interactive then
-                    UIManager:show(InfoMessage:new{
-                        text = _("This book is not in your Bookhoard library yet. Push progress to link it."),
-                        timeout = 4,
-                    })
+                -- Two very different failures share this status. The server's
+                -- resolve handler answers a book miss with JSON
+                -- {"error": "book not found"}; anything else behind a 404
+                -- (an HTML error page) means the route itself is missing —
+                -- a server image predating the resolve endpoint, a reverse
+                -- proxy, or a wrong server URL. Only the former may advise
+                -- pushing to link: acting on a stale-server 404 would push
+                -- this device's first-page position over the server's real
+                -- progress — the very conflict this flow exists to prevent.
+                if result.error == "book not found" then
+                    -- Genuinely unknown to the server (sideloaded book). The
+                    -- legacy push-bootstrap only ever linked such books via
+                    -- fuzzy title/author matching; keep that as a background
+                    -- attempt, but tell interactive users to push explicitly.
+                    if interactive then
+                        UIManager:show(InfoMessage:new{
+                            text = _("This book is not in your Bookhoard library yet. Push progress to link it."),
+                            timeout = 4,
+                        })
+                    else
+                        self:_bootstrapUUIDThenPull(interactive)
+                    end
                 else
-                    self:_bootstrapUUIDThenPull(interactive)
+                    logger.warn("Bookhoard: resolve endpoint returned 404 without a book-not-found body (stale server?)")
+                    if interactive then
+                        UIManager:show(InfoMessage:new{
+                            text = _("Your Bookhoard server does not support this request and may be outdated. Update the server and try again."),
+                            timeout = 5,
+                        })
+                    end
                 end
                 return
             end