I get the infamous "SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified" when running a certain web project, but I don't get it for another project. I've verified they're using the same connection strings and they're running on the same network; on the same machine even.
Obviously there is a difference between the two projects, but I'm at a loss for what it can be. A lot of the back-end code is even shared between the two projects.
This is rather embarrassing, but I can't reproduce the error anymore.
I expect that the connection strings might have been different after all, as we've since had the same problem with other projects, where the port number was missing in the Data Source value of the connection string. Then again, I did check, multiple times, to see if they were different, and they didn't seem to be different…