Is this a logical fallacy?

1. Daniel claims that you should trust God exists because he said so to people.

2. Max claims that it is circular reasoning and it can also be alien's communicating it can be anything.

3. Daniel claims that when you call a person you see that it is that person and he is a human not any other thing because he says so.

4. Hence, gid exists because he said so

The "he said so" is not really true. It was not "he" that said anything but "People/Priests" who said so. So it's really an argument from hearsay . And people as we know lie. Believing that god spoke to someone is an unsupported belief. As long as there are no evidence that indeed the god spoke to the person, it's as valid as rumors/hearsay.
This doesn't mean that they lie necessarily because hallucinations are also real for the person experiencing them. But in that case you can't decide whether it is a hallucination or a god speaking to you. So claiming that is god is speaking to you and not hallucinating without further examination is affirming the consequent .
As for the 3rd statement I have no idea what Daniel is trying to say and how is that relevant to god(s).

1. Daniel claims that you should trust God exists because he said so to people.

As a humorous aside this reminds me of the classic joke in "A Child's Garden of Grass" by Jack S. Margolis and Richard Clorfene. It's a bit dated but if you haven't read the short novelty manual or listened to the record album - they're hysterical!

I smoked weed until I saw God and He told me to stop smoking weed.

The OP is so broad and indeterminable it barely qualifies as a formal fallacy due to the multiple vagaries and equivocations it assumes in its claim. While I agree with Dr. Bo and RE about the circulus probando and other potential categories, it ultimately strikes me as one of those 'thought-terminating clichés' wrapped in an appeal to authority, or, at least, a throwaway line from a Monty Python farce. 

Hey, God said it! Oh, well, end of discussion.

Which God?

There are about 10,000 of them and counting and most of them claim to be THE ultimate godhead. So what is the quality and measure of that inherent trust? That one of them said so? Hmmm. Wouldn't it be logical to check their bona fides first before trusting them? If you were in a foreign country and someone claimed to be king and then when plied for proof responds "because I said so" - should you trust them? 

What exactly did this alleged God say verbatim?

Directly spoken would be one thing, but if relayed through a medium it would be hearsay. If written, what is the original and precise language? Greek? Hebrew? Pig-latin? Esperanto? Was it intended as a riddle, a metaphor, an acronym, or an overt claim?

What is the psychological state of this so-called God candidate?

If we consider our modern-day experience most claims for said godhead are made by schizophrenics and fanatics. So we have to be skeptical. Trust is to be earned and not automatically assigned.

Does He or She have a name? 

He might answer Jehovah, but this is a translation of the original Hebrew Tetragrammaton YHVH (יהוה) YOD HEY VAU HEY as originally revealed to Moses according to the TANAKH.  While there is no consensus about the structure and etymology of the name, the form Yahweh is now accepted almost universally. Why did they choose Jehovah and not the scholarly affirmed YAHWEH? There are also  72 other names the Torah assigns to YHVH He could have used. Among them are:

1.1 YHWH.
1.2 El.
1.3 Eloah.
1.4 Elohim.
1.5 Elohei.
1.6 El Shaddai.
1.7 Tzevaot.
1.8 Jah.

The word God is so generic it is practically meaningless. If you met someone and asked their name and they replied Homo Sapien, you would have to do a little more inquiring to determine their sincerity or intent.

Now we come to the question of existence.

Claiming to be God is NOT proof of existence.

In the fictional book "There and Back Again", the author, Bilbo Baggins claims he is a Hobbit. Okay, we know this to be a work of fiction so merely claiming existence based on a written or spoken statement is easily refutable.

In the Tanakh, Moses claims YHVH spoke to him and revealed his name. Although it is religious tradition to believe Moses wrote the TANAKH and spoke to YHVH it is widely doubted by both religious and secular scholars that the story is even remotely accurate.  As such, existence is not proved simply because it was written in a book no matter what tradition we adhere to or reject.

On the topic of circular reasoning, I discuss how the fallacy becomes more and less fallacious based on the "size" of the circle. Trusting X because X said so is as small of a circle as can be, this is highly fallacious.

Daniel is correct in that if someone agreed with the logic that a person is a person only because they say so, then it would appear to be logically inconsistent to reject God's claim that he is God because he says so. However, this is very likely a strawman fallacy . We identify people by common traits that are easily recognizable and demonstrable. If a person told us they were anything other than a person (i.e., a god, a dog, a mailbox, etc.) we would be skeptical and justified in rejecting their claim without extraordinary supporting evidence. So the conclusion does not follow (non sequitur ).

Even if one were to claim if X said they were a person, and we could believe them based on the fact that they said so (X could be a computer program, a robot, a cartoon cow, etc.), this, too, would be fallacious reasoning. Daniel would then be suggesting that two fallacies cancel each other out rather than it just being twice as fallacious. Here is another example of this:

Dan claims Billy is wrong about claim X because he is ugly.
Max says Dan is guilty of an ad hominem (abusive) .
Dan reminds Max that he thinks Sam is wrong about claim Y because Sam us ugly.
Therefore, Dan claims that Billy is in fact wrong.

In this example, Max is guilty of fallacious reasoning regarding Sam's claim, but this is in no way support for Dan's claim about Billy being wrong, which Dan fallaciously claims.

"God exists because he [God] said so" sounds like begging the question / circular reasoning because we need to assume God exists in order to accept the premise. God couldn't tell anyone he existed if he didn't exist already, so the statement proves nothing it did not already mention.

"When you call a person you see that it is that person and he is a human not any other thing because he says so" - we're trying to compare believing God is real to believing someone is human - let's say, comparing X and Y - but are they closely related enough?

• we have a clear, discriminating definition for 'human' (while we can't even decide if God exists, let alone define it)
• we have empirical (visual) evidence of humans existing - not so much for God
• because of the above, we don't even have to trust someone's word that they are human - they just are.

So we've compared X to Y, but X is really not like Y. That's a weak analogy.