Authlib and GitHub. Error "The redirect_uri MUST match the registered callback"

I use authlib to authenticate with github. In developer settings github I set Authorization callback URL http://127.0.0.1:5000/complete

But everything works very, very strangely, sometimes the authentication works, but more often I get the error:

authlib.integrations.base_client.errors.OAuthError: redirect_uri_mismatch: The redirect_uri MUST match the registered callback URL for this application.

Sometimes I can get an error, and then click on the authentication again and everything will work.

My code:

from app.authentication.oauth import bp
from flask import url_for, render_template, redirect
from app import oauth

@bp.route('/alogin')
def login():
    redirect_uri = url_for('oauth.authorize', _external=True)
    print(redirect_uri)
    return oauth.github.authorize_redirect(redirect_uri)

@bp.route('/complete')
def authorize():
    token = oauth.github.authorize_access_token()
    resp = oauth.github.get('user', token=token) 
    resp.raise_for_status()
    user = resp.json()
    print(token)
    print(user)
    #profile = resp.json()
    # do something with the token and profile
    return redirect(url_for('main.index'))

In my opinion, the uri matches, but it works very strangely

this question is very similar to mine

python-social-auth and github, I have this error "The redirect_uri MUST match the registered callback URL for this application"

But it can't help with my problem.

Ok, I understood what the problem was. I changed 127.0.0.1 to localhost in GitHub app settings. And it works.