I have installed Oracle Database Express Edition 11g and form developer 12c. Until recently, there was no need to develop forms for https://lotoplay.com.ua/. Today I tried to connect the database to the form and received an error
"tns could not resolve the connect identifier specified"
Google and your forum gave a lot of answers, but I still could not figure out what was happening. Tell me how to solve the problem and apologize in advance if I did not find through the search the same topic on the forum.
This error has been written about extensively, all over the 'net. Including this article
Unfortunately you show us nothing about your oracle client configuration, nor any diagnostics you've tried. If I were sitting next to you, I'd first want to know what OS the client is running on. Next I'd want to see the result of 'tnsping <mydbname>'. Next, I'd want to see the contents of the sqlnet.ora file mentioned in the output of 'tnsping', and the content of the tnsnames.ora file in the same directory as 'sqlnet.ora'.
Version 11g is long out of support and obsolete, though that probably has nothing to do with your error.
The error means application/client was not able to resolve TNS alias, which should be located in tnsnames.ora and the format is:
(ADDRESS = (PROTOCOL = TCP)(HOST = myserver.example.com)(PORT = 1521))
(SERVICE_NAME = orcl)