Mobile Printing & Cloud Printing

I have a new modem/router.  My old deskjet is unable to hook up to the wireless network, even though it was successfully hooking up to the wireless network with the old router.  I have tried using the downloadable HP assistant.

I called my internet cable company (Spectrum) they were unable to fix the problem.  I called HP they were unable to fix the problem because my "warranty had expired."

Basically I have tried everything.  HP wants to charge me $20 to set up the old printer on the new wifi network with the new modem/router or they suggest I upgrade my device.  NOT FAIR HP!!!!

So far, the online information I have found has told me to go into the modem/router's configuration utility and find the authentication settings and change them to open.  When I go into my modem/router's configuration there is nothing that says "authentication settings."  So, I am unable to figure out how to do this.  I continually get the message that "your wireless router requires a WPA security passphrase.  The passphrase configured on your hP printer does not match exactly.  Run the wireless network setup to re-enter your wireless network WPA security passphrase."

I have tried this numerous times and checked and double checked that the password was correct.  I even tried changing the password because i thought possibly the password wasn't long enough.  I have tried passwords that are between 10 and 18 digits, but it never works.