We have (DBConnection.ConnectionError) error in multiple places in our production only.

2025-09-03T16:13:51.0122410Z Request: POST /user/employee
2025-09-03T16:13:51.0122511Z ** (exit) an exception was raised:
2025-09-03T16:13:51.0122564Z     ** (DBConnection.ConnectionError) ssl recv: closed (the connection was closed by the pool, possibly due to a timeout or because the pool has been terminated)
2025-09-03T16:13:51.0122619Z         (ecto_sql 3.3.3) lib/ecto/adapters/sql.ex:612: Ecto.Adapters.SQL.raise_sql_call_error/1
2025-09-03T16:13:51.0122667Z         (ecto 3.3.4) lib/ecto/repo/schema.ex:655: Ecto.Repo.Schema.apply/4
2025-09-03T16:13:51.0122737Z         (ecto 3.3.4) lib/ecto/repo/schema.ex:263: anonymous fn/15 in Ecto.Repo.Schema.do_insert/4
2025-09-03T16:13:51.0122790Z         (my_app 4.0.0) lib/my_app/pension/workflow.ex:39: MyApp.Pension.Workflow.create_pension/2
2025-09-03T16:13:51.0122840Z         (ecto_sql 3.3.3) lib/ecto/adapters/sql.ex:886: anonymous fn/3 in Ecto.Adapters.SQL.checkout_or_transaction/4
2025-09-03T16:13:51.0122891Z         (db_connection 2.2.1) lib/db_connection.ex:1427: DBConnection.run_transaction/4
2025-09-03T16:13:51.0122966Z         (my_app 4.0.0) lib/my_app/controllers/employee_controller.ex:328: MyAppWeb.EmployeeController.create/3
2025-09-03T16:13:51.0123016Z         (my_app 4.0.0) lib/my_app/controllers/employee_controller.ex:1: MyAppWeb.EmployeeController.action/2

below is the function MyApp.Pension.Workflow.create_pension/2

 def create_pension(changeset, current_user) do
    # here we are inserting a new record into pensions table
    case Repo.insert(changeset) 
	.......

the below is the another function the error is repeating

2025-09-03T15:16:43.7459272Z 15:16:43.744 [error] Task #PID<0.5423.30> started from #PID<0.5443.30> terminating
2025-09-03T15:16:43.7459738Z ** (DBConnection.ConnectionError) ssl recv: closed (the connection was closed by the pool, possibly due to a timeout or because the pool has been terminated)
2025-09-03T15:16:43.7459826Z     (ecto_sql 3.3.3) lib/ecto/adapters/sql.ex:612: Ecto.Adapters.SQL.raise_sql_call_error/1
2025-09-03T15:16:43.7459892Z     (ecto_sql 3.3.3) lib/ecto/adapters/sql.ex:545: Ecto.Adapters.SQL.execute/5
2025-09-03T15:16:43.7459998Z     (my_app 4.0.0) lib/my_app_web/plugs/user_auth_plug.ex:209: MyAppWeb.UserAuthPlug.update_last_seen!/2
2025-09-03T15:16:43.7460059Z     (elixir 1.13.4) lib/task/supervised.ex:89: Task.Supervised.invoke_mfa/2
2025-09-03T15:16:43.7460121Z     (elixir 1.13.4) lib/task/supervised.ex:34: Task.Supervised.reply/4
2025-09-03T15:16:43.7460179Z     (stdlib 3.14.2.2) proc_lib.erl:226: :proc_lib.init_p_do_apply/3
2025-09-03T15:16:43.7460262Z Function: #Function<0.37496757/0 in MyAppWeb.UserAuthPlug.put_current/3>
2025-09-03T15:16:43.7460334Z     Args: []

below is the MyAppWeb.UserAuthPlug.update_last_seen! method

  def update_last_seen!(%{id: id}, repo) when not is_nil(id) do
    "users"
    |> from
    |> where(id: ^id)
    |> update(set: [last_seen_at: ^NaiveDateTime.utc_now()])
    |> repo.update_all([])

    :ok
  end

We tried increasing the database pool size from 36 to 50. still it didn’t show any improvement. Can someone please help me here.