Host name, Portal Number, Service Username, and password are confirmed to be accurate. QA env install worked properly pointing to same external Oracle database
Standalone 14.4.2
Installation
Oracle having issue with special character in the password.
https://asktom.oracle.com/ords/asktom.search?tag=symbols-to-avoid-in-an-oracle-password
Do not use the following in an Oracle password.
# at the beginning
\
"
'
` (backtick)
$
!
We found "!" was being used in the password of this IM install which was not being used in their other QA environment. Reset password to not use special characters containing " #,/,",',$,!" and tried again. Special character caused the "invalid connection error". Once no special character was used in the Oracle password, connection worked without issue.
https://knowledge.broadcom.com/external/article?articleNumber=143790