Hi @Bala Narasimha Challa ,
If you look in MSDN RAISERROR (Transact-SQL) you can read the following in the arguments section for severity
Severity levels from 0 through 18 can be specified by any user. Severity levels from 19 through 25 can only be specified by members of the sysadmin fixed server role or users with ALTER TRACE permissions. For severity levels from 19 through 25, the WITH LOG option is required. Severity levels less than 0 are interpreted as 0. Severity levels greater than 25 are interpreted as 25.
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