When the diploma does not seem real, it can indeed be a fake. It is not necessarily against the law to issue or purchase such a diploma. On the other hand, claiming the degree is legit is asking for trouble. When in doubt, you can always ask for transcripts.
2. Phony companies
When you hear the name of the company for the very first time it does not mean that the person is lying to you. It only means that you ought to do some research before offering the person a position.
Browse the internet. If the address does not correspond to one they gave on the resume, the company may have moved. Or, it is possible that the person is hoping that you will not check all the details.
Don’t call the phone number presented as a professional reference. Call reception and ask to speak to the person whose name written on the resume. This is better because sometimes the number will only connect you to the candidate’s friend who is going to give a false reference, pretending to be someone else.
3. Inflated job titles
Perhaps the title seems a little bit too wordy. Perhaps the progress on the corporate ladder from an entry-level position was too fast. Everything could be fine, just call the company to find out.