If you are not regularly deleting the log files that are created by the SQL server, the log files can increase in size until there is no free disk space on the server. To recover disk space, regulary truncate the log files by running the Optimize command in Model Explorer. You can also use the spRebuildReorganiseIndexesAndTruncateLog stored procedure.

For more information about stored procedures, refer to the following SQL Server help topic:

Execute a Stored Procedure

https://docs.microsoft.com/sql/relational-databases/stored-procedures/execute-a-stored-procedure?view=sql-server-2017

For more information about backing up and deleting log files, see the Administration chapter of the Modeler help.