Steps to reproduce:

1. Deploy zabbix-agent 5.2
2. Install ODBC client unixODBC 2.3.7 in Zabbix Server
3. Configure Host Macros: {$MSSQL.USER} and {$MSSQL.PASSWORD}
4. Apply template in host, but don´t work

Result:

In Logs Zabbix Server:

707:20201201:133200.618 item "HOST-CLIENT-DB:db.odbc.get[get_status_variables,"\{$MSSQL.DSN}"]" became not supported: Cannot connect to ODBC DSN: [SQL_ERROR]:[IM002][0][[unixODBC][Driver Manager]Data source name not found and no default driver specified]
708:20201201:133203.624 item "HOST-CLIENT-DB:mssql.average_wait_time" became not supported: Cannot evaluate expression: "Cannot evaluate function "prev()": not enough data.".
708:20201201:133203.624 item "HOST-CLIENT-DB:mssql.average_latch_wait_time" became not supported: Cannot evaluate expression: "Cannot evaluate function "prev()": not enough data.".
708:20201201:133203.624 item "HOST-CLIENT-DB:mssql.percent_of_adhoc_queries" became not supported: Cannot evaluate expression: "Cannot evaluate function "last()": not enough data.".
708:20201201:133203.624 item "HOST-CLIENT-DB:mssql.percent_recompilations_to_compilations" became not supported: Cannot evaluate expression: "Cannot evaluate function "last()": not enough data.".
709:20201201:133204.625 item "HOST-CLIENT-DB:mssql.scan_to_search" became not supported: Cannot evaluate expression: "Cannot evaluate function "last()": not enough data.".
736:20201201:133500.398 discovery rule "HOST-CLIENT-DB:db.odbc.discovery[availability_groups,"\{$MSSQL.DSN}"]" became not supported: Cannot connect to ODBC DSN: [SQL_ERROR]:[IM002][0][[unixODBC][Driver Manager]Data source name not found and no default driver specified]
737:20201201:133501.450 discovery rule "HOST-CLIENT-DB:db.odbc.discovery[dbname,"\{$MSSQL.DSN}"]" became not supported: Cannot connect to ODBC DSN: [SQL_ERROR]:[IM002][0][[unixODBC][Driver Manager]Data source name not found and no default driver specified]
736:20201201:133502.451 discovery rule "HOST-CLIENT-DB:db.odbc.discovery[local_db,"\{$MSSQL.DSN}"]" became not supported: Cannot connect to ODBC DSN: [SQL_ERROR]:[IM002][0][[unixODBC][Driver Manager]Data source name not found and no default driver specified]
737:20201201:133503.451 discovery rule "HOST-CLIENT-DB:db.odbc.discovery[mirrors,"\{$MSSQL.DSN}"]" became not supported: Cannot connect to ODBC DSN: [SQL_ERROR]:[IM002][0][[unixODBC][Driver Manager]Data source name not found and no default driver specified]
736:20201201:133504.504 discovery rule "HOST-CLIENT-DB:db.odbc.discovery[non-local_db,"\{$MSSQL.DSN}"]" became not supported: Cannot connect to ODBC DSN: [SQL_ERROR]:[IM002][0][[unixODBC][Driver Manager]Data source name not found and no default driver specified]
737:20201201:133505.556 discovery rule "HOST-CLIENT-DB:db.odbc.discovery[replicas,"\{$MSSQL.DSN}"]" became not supported: Cannot connect to ODBC DSN: [SQL_ERROR]:[IM002][0][[unixODBC][Driver Manager]Data source name not found and no default driver specified]

This Host it´s in another WAN, routed with port forward (tcp 10050 and 1433) behind a firewall, with full access to my Zabbix Server. 

The MSSQL Server it´s in a Ubuntu Server, and has a template Linux working.

Please, What can I do to resolver this problem?

Thanks.