i signup and give me this error Doctype html error

[akifkhan6556]

cannot signup show this error ... Docttype html see image in the link..
copy link and past in the search bar and click enter......

https://drive.google.com/file/d/1wxOLX3pfe7Ccnt32o1FP4SK3e0BsSmsZ/view?usp=sharing

[Swati4star]

@prabhakar267

[ritesh-pandey]

Is this because the Heroku app is not up? https://project-travel-mate.herokuapp.com/api/

[ankita010899]

Can you please tell me how to resolve the doctype error...the app shows html code in the snackbar after clicking on sign up

[karan05-kj]

Same error... (In sign up Dcotype html error) How to solve... Plzz anyone help... @ritesh-pandey @Swati4star @prabhakar267

[ghost]

Does anyone know how to fix this error? Can Someone help ?

[MuhammadImran2]

Please solve this is issue