In our humble opinion, “signs” here refers to the verses of the Quran and not other signs mentioned numerous times elsewhere in the Quran such as vegetation, the mountains, the heavens etc. Credence to this notion is see in this alternate translation: “And indeed We have sent down to you manifest Ayat (verses) and none disbelieve in them but Fasiqun (those who rebel against Allah’s command).”
Regardless, we should never reject and signs provided to us by Allah SWT.
