Class with methods to retrieve data with Linq to sql
I can see some room for improvement:


Most importantly, you shouldn't hide exceptions like this. You should most likely let the exceptions bubble up and let the called decide what to do when an exception happens. And if you return null, it means you will either have to add null checks everywhere, or you will get NullReferenceException instead of the exception that actually caused the problem, which makes it harder to debug.
You don't need to add items into the list one by one, you can do it all at once using AddRange(). Or even better, just use ToList():

return crmTenants.ToList();

This one is really minor, but the query from tenant in context.CrmTenant select tenant can be simplified to just context.CrmTenant, the LINQ doesn't do anything useful there.


#1 is by far the biggest issue, I think, because it shows an error in your design. #2 and #3 could just simplify your code a bit.