That version of SQL Server 2008 does not support TLS 1.2. You need to install Service Pack 4, and then I think there is a GDR for SP4 that gives you support for TLS 1.2.
SP1 for SQL 2008 has been out of date since 2010 or so. I don't know why you think you cannot upgrade, but if you insist on running that version, you will be paying the price for kludges. Or not being able to use your Excel macro.
The workaround? Install a Virtual Machine with some older operating system and run the macro from that machine, maybe.