Yesterday Admiral Rogers testified at a SSCI hearing. You can find a video excerpt here. A rough transcript of the questions from Senator Cotton:
Are the communications of the senior-most advisers to the president of the United States, even those that may be unclassified, a top priority for foreign intelligence services, in your opinion?
If an NSA employee came to you and said, "Hey, boss, we have reason to believe that Russian Foreign Minister Sergei Lavrov or Iranian Foreign Minister Javad Zarif is conducting official business on a private server." How would you respond?
From a foreign intelligence perspective, that represents opportunity.