Please let me know if you need any modifications or if this meets your requirements.
Navigate to > TPM 2.0 Security (or PTT on some models). Ensure TPM Security and TPM On are checked/enabled.
Download the latest Dell Vostro 5568 System BIOS and the Dell TPM 2.0 Firmware Update Utility from the Official Dell Support Site .
Reconnect the batteries and AC power, then check the BIOS again. Solved: Dell Vostro 5568 - Alert! TPM device not detected.