WebUI login keeps prompting for login -

[odhiambo]

Hello everyone,
I new to mailtrain. I have installed it on a Debian 12 box using Docker.
Everything went well until the time to login to https://mailtrain.mydomain.name.
It does not allow me in using the correct password (set in the docker-compose.yml). It just keeps prompting for the admin login.
When I put in the wrong password, it says "Invalid username or password.", which makes me believe I have the right password.
I am running mailtrain behind Apache reverse proxy and and there is no error logged for the vhost.
When I tail the logs of the container, this is what I see:

info HTTP POST /rest/login 500 240.527 ms - 67
info HTTP POST /rest/login 500 263.057 ms - 67
info HTTP POST /rest/login 500 237.128 ms - 67

Any clues as to what could be the issue?