A technician receives an invalid certificate error when visiting a website.

 Date and time is the most likely cause of the issue. The date and time settings on a workstation affect the validity of the certificates used by websites to establish secure connections. If the date and time are incorrect, the workstation may not recognize the certificate as valid and display an invalid certificate error. Other workstations on the same local network may not have this issue if their date and time are correct. User access control, UEFI boot mode, and log-on times are not likely causes of the issue. User access control is a feature that prevents unauthorized changes to the system by prompting for confirmation or credentials. UEFI boot mode is a firmware interface that controls the boot process of the workstation. Log-on times are settings that restrict when a user can log in to the workstation. None of these factors affect the validity of the certificates used by websites. References:

Official CompTIA learning resources CompTIA A+ Core 1 and Core 2, page 14

CompTIA A+ Core 1 (220-1101) and Core 2 (220-1102) Cert Guide, page 456