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Try by configuring the order to negotiate authentication by adding the following property to the JVM configuration and re-starting Jira:

-Dsvnkit.http.methods=Basic,Digest,Negotiate,NTLM

Please, read this Atlassian's documentation for how to add the property above to  your Jira instance configuration startup:

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• Add an URL as svn-ssh://my.server.addr/foo/bar (no username in the URL)
• Add the username you want to connect with in the Basic Authentication section.
• Copy the rsa_id file to the /var/atlassian/application-data/jira and then specified /var/atlassian/application-data/jira/rsa_id in the field for the key

ERROR: relation "ao_2b6364_svn_app_conf" does not exist Position: 19

Under some circumstances the app is unable to detect the database vendor and the configuration page shows a massive failure:

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This has been reported for some PostgreSQL database instances.

Please follow these instructions to resolve it:

• Upgrade Subversion ALM for the 9.3.3 version or above
• Execute this sentence: INSERT INTO "AO_2B6364_SVN_APP_CONF"("KEY_NAME", "VALUE") VALUES('DATABASE_VENDOR', 'POSTGRESQL');
• Re-enable the app in order the changes to take effect.

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