Good question 👍 Let me explain clearly why that happens:
🔁 What “Flexible SSL” does
- With Flexible SSL, Cloudflare accepts HTTPS from the browser → Cloudflare,
but Cloudflare connects to your server over plain HTTP (not HTTPS).
🔁 What happens if your app forces HTTPS
- Many apps (via Nginx, Apache, Express, etc.) are set to force HTTPS redirects — if a request comes in over HTTP, the app says: “No, go to https://…”.
- But Cloudflare is calling your server over HTTP.
- So the server responds: “Please use HTTPS”.
- Cloudflare tries HTTPS → still uses Flexible mode → goes back to HTTP when talking to your server.
- This repeats forever → 🔄 infinite redirect loop.
✅ How to fix
- If your server has a valid SSL certificate (even self-signed or Let’s Encrypt):
→ Use “Full” or “Full (Strict)” SSL mode in Cloudflare. - If your server truly can’t do HTTPS:
→ Don’t force HTTPS in your app/web server, or turn off proxy (grey cloud).
👉 So the loop happens because Cloudflare is lying to your server (it says “I’ll handle HTTPS” but only asks your server over HTTP), while your server insists on HTTPS. They keep bouncing each other endlessly.
Do you want me to check which SSL mode your Cloudflare is currently set to and tell you which one fits your setup?
About the Author
Dimas Widiantoro is a SaaS Growth Strategist with more than 12 years of experience helping startups and scale-ups across APAC and Europe. He specializes in market development, user acquisition, retention strategies, and product-led growth.
Throughout his career, Dimas has built and scaled startups from the ground up to millions of users, working with diverse teams in product, marketing, and technology. He has led global growth and retention initiatives, managed multi-million user acquisition campaigns, and supported digital transformation projects across industries. Notably, he played a key role in scaling Brainly to 350M+ monthly users, and he continues to advise and support new ventures today.
- 🚀 Scaled multiple startups from zero to millions of users
- 📈 Expertise in CRM, performance marketing, and growth strategy
- 🤝 Currently supporting new ventures & sharing portfolio at codify.my.id
Dimas holds a MSc in Strategic Business from the University of Agder (Norway) and is pursuing a PhD in Economics at Krakow University of Economics. He is fluent in English and Bahasa Indonesia, with working proficiency in Polish.
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