diff --git a/JobTrackerApi/Services/StartupInitializationExtensions.cs b/JobTrackerApi/Services/StartupInitializationExtensions.cs
index cfde895..1cf1a36 100644
--- a/JobTrackerApi/Services/StartupInitializationExtensions.cs
+++ b/JobTrackerApi/Services/StartupInitializationExtensions.cs
@@ -1937,7 +1937,14 @@ public static class StartupInitializationExtensions
                     // Hot-path composite indexes for tenant-scoped list/board/stats/analytics
                     // (OwnerUserId + IsDeleted) and reminders (OwnerUserId + FollowUpAt).
                     TryCreateIndex("JobApplications", "IX_JobApplications_OwnerUserId_IsDeleted", "`OwnerUserId`(191), `IsDeleted`");
-                    TryCreateIndex("JobApplications", "IX_JobApplications_OwnerUserId_FollowUpAt", "`OwnerUserId`(191), `FollowUpAt`");
+                    // FollowUpAt is `text` on MariaDB (the migration was scaffolded against SQLite, which
+                    // stores DateTimeOffset as TEXT). A text column cannot be indexed without a prefix
+                    // length, so without one this index ALWAYS failed the 3072-byte key check, was caught
+                    // and skipped on every boot, and left the follow-up reminder query unindexed — while
+                    // logging a "Specified key was too long" line the deploy runbook flags as a rollback
+                    // signal. Prefix it like Status(50) below. ISO-8601 date strings sort lexicographically,
+                    // so a 20-char prefix ("YYYY-MM-DD HH:MM:SS") keeps the index useful for the reminder scan.
+                    TryCreateIndex("JobApplications", "IX_JobApplications_OwnerUserId_FollowUpAt", "`OwnerUserId`(191), `FollowUpAt`(20)");
                     // Status is longtext in MySQL (see JobTrackerContext.OnModelCreating), so it
                     // needs an explicit prefix length to be indexable under MariaDB's key-length rules.
                     TryCreateIndex("JobApplications", "IX_JobApplications_OwnerUserId_IsDeleted_Status", "`OwnerUserId`(191), `IsDeleted`, `Status`(50)");