At this point in Plato's Apology, Socrates has been convicted of the charges against him and finds himself subject to a sentence of death. Socrates observes that most people regard death as a bad thing and something to be feared. Socrates, however, reasons that death is not a bad thing because his personal daimon always warns him if he is about to make some sort of mistake or error. Accordingly, Socrates reasons that because his personal spirit did not oppose him in anything he had done or said on the day of the trial, that what happened to him on that day must be a good thing. The silence of the daimon leads Socrates to "regard this as a proof that what has happened to me is a good, and that those of us who think that death is an evil are in error" (Benjamin Jowett translation).
So, in this situation, Socrates reasons as follows: My daimon warns me when bad things happen. My daimon did not warn me, therefore getting sentenced to death is not a bad thing.
There are a number of possible fallacies that this might be classified as. It could fall under the heading of an "oversimplified cause." Just because Socrates' daimon didn't warn him does not mean that death is not a bad thing or to be feared.
In the Cum hoc fallacy, a person incorrectly assumes that because two events coincide they must be related. Again, just because Socrates daimon does not oppose him on the day that he gets sentenced to death does not mean that death is neither bad nor to be feared.
I suppose some might also categorize this as a "hasty generalization" since Socrates may be relying on an unrepresentative example to arrive at his conclusion.
In short, there are a number of logical fallacies that Socrates' reasoning might be classified as in this situation.