I am not able to add new language

Can you please find and post some useful error messages?

https://localise.biz/wordpress/plugin/faqs/debug-info

Hello @timwhitlock

Not any error message showing when i enable debug log

Usually a blank screen means a fatal error during execution. A fatal error should yield error messages if things are set up properly.

I can’t debug a blank screen

Hello @timwhitlock

I am getting Uncaught Error: Call to undefined function nocache_headers() this error in my error log

Ok, well Loco Translate does not call nocache_headers directly. What is the rest of the message showing file and line number? Ideally we need the stack trace to establish fault.

I assume you’ve disabled all other plugins and switched to a stock theme as per the advice in my link?