There is no password recovery option in the web panel UI.
The password can be recovered using the database (SQL request).
Login to your server by SSH and run the following commands:
# sudo su postgres
(enter your SSH password here)
# psql hmdm
hmdm=# select * from users where name='admin';
(you will get a row, the first parameter is the admin user id, usually it is 1 but may be different for other users.
hmdm=# update users set password=md5('new-password') where id=1
(this command recovers the password, type the desired password instead of new-password).