ORA-16086 standby database does not contain available standby logfiles

Cause: The primary database is in "no data loss" mode, but the standby database does not contain any "standby logfiles".

Action: Add one or more standby logfiles to the standby database. This can be done while the standby database is mounted.
Increase the recovery area size of standby database. You can check the location of archived redo log file by,
SQL> connect / as sysdba
SQL> archive log list

If you see that archive destination is USE_DB_RECOVERY_FILE_DEST then the location will be specified by parameter DB_RECOVERY_FILE_DEST.
SQL> SHOW PARAMETER DB_RECOVERY_FILE_DEST
+RECOVERY

Note that you have sufficient storage under +RECOVERY and also you have set proper size of the parameter db_recovery_file_dest_size.

To check the size of parameter db_recovery_file_dest_size issue,
SQL> show parameter db_recovery_file_dest_size

In order to increase the size of db_recovery_file_dest_size parameter issue,
SQL> alter system set db_recovery_file_dest_size = 1000G scope=both sid='*';