What did Tacitus claim was the cause of Agricola's death?

When Agricola died, Tacitus insinuated Domitian poisoned him. There was no real evidence to this claim. However, it seemed to be common knowledge that Domitian was jealous of Agricola's successes in the military. Domitian was also the emperor that pulled Agricola from Britain and got his men to persuade Agricola from taking a government post.