You may receive the following error when accessing sqlplus or launching eHealth OneClick (this error more likely appears on the old ehealth versions from 6.0 to 6.3.1).
SQL*Plus: Release 126.96.36.199.0 - Production on Fri Nov 20 09:34:50 2015
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ORA-00257: archives error. Connect internal only, until freed.
eHealth 6.0.x, 6.1.x, 6.2.x, 6.3.x
Check the partition disk space and make sure that $NH_HOME (the directory path where the eHealth application is installed) has at least 5 GB free disk space, and that the same is true for $NH_ORACLE_HOME (the directory path where the Oracle software is installed). Also make sure that none of the partition disk usage is over 95%.