OnePlus two will not let me go in mtp mode or USB debugging need help pls

I have a oneplus two that I just bought used. Im trying to u nlock the bootloader so I can flash twrp and root it however when I turn on debugging from developer options it doesn't show on my pc all it does it charge. It's in mtp mode developer options are on USB config is set to mtp or file transfer(I've tried it on charge and ptp all it will do is charge audio midi and rndis are options but it won't click on those) I've already look thru Google for days now and tried any work around or whatever that I've come across to no avail. I also spoke with the previous owner who told me that he used it right before selling it to me to transfer his files. IDK what else to do so hopefully someone has dealt with this before and has a fix..it's a great phone as is but it's even better rooted ;)