I am using desktop turbotax. When I click "Transmit Returns Now", nothing happens. No error message, it just doesn't file. My app is up to date and internet works

Try signing out and exiting the software completely. Restart and sign in and try to click Transmit Returns Now again.  Also, please see the Help Article here for additional troubleshooting.  

Did you give it enough time for the servers to respond?

Now is crunch time.

I had tried this multiple times with no luck.

I believe I've found the reason though. TurboTax is just incompatible with efile this year in Indiana. Multiple other threads report identical errors. I will be filing by mail and requesting a refund for the efile charge.

https://ttlc.intuit.com/community/taxes/discussion/when-i-click-on-transmit-my-returns-now-nothing-happens/00/645198

Same question asked in this link. The answer might help. I haven't faced this problem before.