What version of OpenCart are you reporting this for?
OC 3.0.3.7

Describe the bug

Unable to log into the dashboard after changing the timezone from the default of none.

To Reproduce
Steps to reproduce the behavior:

System -> Settings -> Store -> Local -> Time Zone

I set the time zone to America/Detroit (-5:00) and applied the changes. The session ended and was unable to log in.

Expected behavior
To be returned to the dashboard with changes applied.

Screenshots / Screen recordings

Server / Test environment (please complete the following information):

Local development? Deployed to a web server? - Production server
Operating system - Win2012R2
PHP version - 7.4
Web Server version - IIS8
Browser(s) tested with [e.g. chrome, safari - if applicable] - Chrome

Extra Notes

I was able to get out of the situation by changing the session engine from db to file in the system/config/default.php and system/config/catalog.php files.