I saw in the console that the errors were due to the "Mixed Content" of the http protocol. Whereas the site should work on https.
Mixed Content: The page at 'https://speakandgo.education/lms/installation/' was loaded over HTTPS, but requested an insecure XMLHttpRequest endpoint 'http://speakandgo.education/lms/installation/?task=installation.dbcheck&format=json'. This request has been blocked; the content must be served over HTTPS.
Mixed Content: The page at 'https://speakandgo.education/lms/installation/' was loaded over HTTPS, but requested an insecure XMLHttpRequest endpoint 'http://speakandgo.education/lms/installation/'. This request has been blocked; the content must be served over HTTPS.
Can you please tell me where this can be fixed?
P.S. This is our production server. We can provide access to it, but this is an extreme measure.