DB --- Cannot shrink log file because all logical log files are in use

When I try to Shrink a Log File (wow!! It grows to 3GB, testing server) in SQL server, it show the message
"Cannot shrink log file because all logical log files are in use"
After finding a workable solution, Microsoft provide the solution
Shrinking the Transaction Log in SQL Server 2000 with DBCC SHRINKFILE

Shrinking the log in SQL Server 2000 is no longer a deferred operation. A shrink operation attempts to shrink the file immediately. However, in some circumstances it may be necessary to perform additional actions before the log file is shrunk to the desired size.

DBCC SHRINKFILE(UR_LOG, 2)
BACKUP LOG UR_DB WITH TRUNCATE_ONLY
DBCC SHRINKFILE(UR_LOG, 2)

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