Unable to save Metabase question

I'm trying to add a new question to an existing dashboard but unable to do it even after multiple tries. I tried on Chrome Version 90.0.4430 and Safari Version 14.0.3 but to no luck.
I paste the query and return results but when I click on Save, there's a green prompt called 'Success' but nothing happens post that. Attaching a screenshot from the console:

I'm stuck and do not know how to proceed. Please help!

Hi @nishantb
Post "Diagnostic Info" from Admin > Troubleshooting.
And check the logs for more detailed errors - Admin > Troubleshooting > Logs.
If you're using a reverse-proxy that is modifying the requests, then you need to disable that:

Hi @flamber, thanks for the response. Below is the "DIagnostic Info" :

"browser-info": {
"language": "en-GB",
"platform": "MacIntel",
"userAgent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/90.0.4430.212 Safari/537.36",
"vendor": "Google Inc."
"system-info": {
"file.encoding": "ANSI_X3.4-1968",
"java.runtime.name": "OpenJDK Runtime Environment",
"java.runtime.version": "1.8.0_242-b08",
"java.vendor": "Oracle Corporation",
"java.vendor.url": "http://java.oracle.com/",
"java.version": "1.8.0_242",
"java.vm.name": "OpenJDK 64-Bit Server VM",
"java.vm.version": "25.242-b08",
"os.name": "Linux",
"os.version": "4.14.171-105.231.amzn1.x86_64",
"user.language": "en",
"user.timezone": "Asia/Calcutta"
"metabase-info": {
"databases": [
"hosting-env": "unknown",
"application-database": "mysql",
"application-database-details": {
"database": {
"name": "MySQL",
"version": "5.6.44-log"
"jdbc-driver": {
"name": "MariaDB Connector/J",
"version": "2.5.1"
"run-mode": "prod",
"version": {
"tag": "v0.35.0",
"date": "2020-04-01",
"branch": "hide-query-editor",
"hash": "79bde74"
"settings": {
"report-timezone": "Asia/Calcutta"

Also this is the error screenshot after which nothing happens:

Metabase requires MySQL 5.7.7 or newer for the application database, so that's the problem:
And you're using a custom build of Metabase. Latest release is 0.39.2: