USB2517 USB hub unable to enumerate
I'd recommend for you to always read the datasheet of the IC you are designing a circuit for, you can NOT send your design for fab without scrubbing through every little detail. Also, take a look at Microchip's reference design for that USB hub and compare with yours: http://ww1.microchip.com/downloads/en/DeviceDoc/evb2517sch.pdf

Here are the main concerns:


Pin 25 and Pin 62 can NOT be floating, there are important core and PLL power output and need decoupling capacitors attached. When you see "must have" in the datasheet, it's not a fluke... The hub is most likely not booting because of those missing capacitors.







Where are all your decoupling capacitors for the VDD33 inputs? Are you not showing them or are they none? Please make sure you follow the datasheet and reference design recommendation for proper decoupling.
If you intend to use USB High-Speed (480Mbps) then use lower capacitance ESD diodes. The ones you are using (esd9b3.3st5g) have too much capacitance (15pF) and will cause poor signal quality, find some ESD diodes with under 1pF of parasitic capacitance instead.
Do not tie RESET_N to +3V3 without a pull-up resistor (10k or so), how would you be able to reset the hub for troubleshooting/testing?