How to defeat ORA-01017: invalid username/password; logon denied?

Question

Oracle

I'm trying to deploy Oracle18xe yf aws.amazon.com/ec2 I
created a virtual machine with OS RH7, forwarded ports 22 1521 5500 I
set everything according to the instructions https://docs.oracle.com/en/database/oracle/oracle-...
No parameters changed, all by default. Everything was set.
It's time to connect: I checked it locally, the connection works SQLPLUS connects.
I try to connect from outside, I get an error ORA-01017: invalid username/password; logon denied?
I don’t know if this is related or not, but https://IP:5500/em is also not available, although the port is assigned in the database
Who faced it? how to win?

Lister settings
DEFAULT_SERVICE_LISTENER = XE
LISTENER =
(DESCRIPTION_LIST =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = ip.ec2.internal)(PORT = 1521))
(ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1521))
)
)
tns on server
XE =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = ip.ec2.internal)(PORT = 1521))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = XE)
)
)
LISTENER_XE =
(ADDRESS = (PROTOCOL = TCP)(HOST = ip.ec2.internal)(PORT = 1521))

Answer 1

If someone will be useful. I solved the problem by changing the password for SYS SYSTEM users from the local machine from under sysdba.
It remains unclear why the same is done in guides and vids, and there is no such problem. By the way, the password was changed to another and then back to the previous one.