Front end cannot get data from backend after install ssl certificate

I'm a novice in deployment. My web application is deployed on aws ec2 instance (ubuntu 20.04). Front end is deployed on apache2. Before I install ssl certificate, everything goes fine, and I can access it through http://*****.***. After I install SSL, when I access https://*****.***, I find my front end application can not get data from backend, but the interface shows properly.

My backend run on 4000. I tested my api. I still can access data through http://*****.***:4000, but got nothing when accessing https://*****.***:4000.

Can anyone tell me what should I do now? Thank you in advance.

https://stackoverflow.com/questions/65948632/front-end-cannot-get-data-from-backend-after-install-ssl-certificate January 29, 2021 at 12:06PM