I've made a ranger subclass and it says: 

• This homebrew Subclass has data mapped to it that is licensed content or private homebrew. This typically occurs when licensed or private homebrew spells are linked to the Subclass.

As far as I can see the only thing this could be is that I've linked actual spells to the class. do I need to make custom spells in order to publish it?

Sub class is: https://www.dndbeyond.com/subclasses/809074-mounted-ranger-lesser-wyvern

Any help would be appreciated 

You can only link spells from the Basic Rules & SRD, and the Elemental Evil Player’s Companion and still publish your subclass. That list is here:

https://www.dndbeyond.com/spells?filter-class=0&filter-search=&filter-verbal=&filter-somatic=&filter-material=&filter-concentration=&filter-ritual=&filter-sub-class=&filter-source=1&filter-source=4

if you attach any official spells not on that list, you won’t be able to publish your subclass. If you make a duplicate of those spells and publish them, they will be rejected because they are not your original work.

I'll take a look, thankyou for the information

It’s still not working for me

Quote from Holycrusader5637 >>

It’s still not working for me

 
If you are still getting the same error message as the OP, then you must still have either an official spell that is not free content mapped to your homebrew, or an unpublished homebrew spell mapped to it. I refer you to the General FAQ #s 7, 8, & Ω: (https://www.dndbeyond.com/forums/dungeons-dragons-discussion/homebrew-house-rules/131411-a-homebrewers-how-to-faq).

Quote from IamSposta >>

You can only link spells from the Basic Rules & SRD, and the Elemental Evil Player’s Companion and still publish your subclass. That list is here:

https://www.dndbeyond.com/spells?filter-class=0&filter-search=&filter-verbal=&filter-somatic=&filter-material=&filter-concentration=&filter-ritual=&filter-sub-class=&filter-source=1&filter-source=4

if you attach any official spells not on that list, you won’t be able to publish your subclass. If you make a duplicate of those spells and publish them, they will be rejected because they are not your original work.

 Thank you for this. Sposta you have really been a help in general across D&D! Thank you sir!

Happy to help.

Heyo Sposta, is there a place I can find the new list since the addition of the 2024 Free rules? 

In other words, what is the current full list of spells I can add to homebrew  without the error? This list I have in mind includes 2014 and 2024 free rules along WITH any other free to use content like the SRD or Elemental Evil Player’s Companion. 

EDIT: Nevermind lol, I figured it out by making a successful Investigation check ;) I will add the link for the new list in my next post

https://www.dndbeyond.com/spells?filter-search=&filter-verbal=&filter-somatic=&filter-material=&filter-concentration=&filter-ritual=&filter-source=1&filter-source=148&filter-source=4&filter-partnered-content=f

My sincerest apologies, I would have responded sooner had I noticed it. To answer your question, yes. One of the first updates I made to the homebrewers’ “How-To” FAQ was to update the links that point towards the “free content” spells. However, I see you have already successfully passed your investigation  heck and done it for yourself. 👍😁😉