It’s good to be dbowner in MS SQL server, but it’s easy to forget about permissions for other users. I created a procedure and tried to execute it from technical account. And I've got the error that user can not execute procedures.

To allow mssql permission to execute stored procedure in Microsoft SQL Server Management Studio you should go to your database, expand Programmability and right click on your procedure, select "Properties".

In windows "Properties" select tab "Permissions", click on "Search" button and enter you user name. Then set "Grant" checkbox in "Execute" row. Press Ok.