ModelBuilder Rebuild Indexes tool - datasets are red underlined?

[AndreaB_]

Hi all,

I'm trying to create a model to schedule to run overnight. I am having a lot of problems with the rebuild indexes tool not liking my data connection to my SQL geodatabase. Here is a screenshot where the datasets are underlined in red. I have redone the sde connection string, rechecked the data, saved, closed the aprox, and reopened arpx and I see the same thing in the tool. 

Does the red underline mean it doesn't like it? I can find no documentation on this.

Thank you!