We recently came across an issue when trying to register some custom SQL CLR assemblies we have created on SQL Server 2017 v14.0.3238.1.
First of all, these assemblies require that they have External Access Permission, as they call external APIs. It seems that this issue is only appearing when trying to run them on an MSSQL Server that is hosted on a Linux Environment.
In addition, we have tried creating asymmetric keys (both with SN.exe tool from Microsoft SDKs and through VS 2017) and also signing these CLR assemblies, without any luck. (Followed instructions as found on: https://techcommunity.microsoft.com/t5/SQL-Server-Support/Deploying-SQL-CLR-assembly-using-Asymmetric-key/ba-p/316727)
When trying to register the assemblies, we are receiving the error:
"Assembly 'Sample_CLR' cannot be loaded because this edition of SQL Server only supports SAFE assemblies."