My ITR filing got stuck post payment and it doesn't acknowlege the payment. How to resolve this?

I paid the tax on the payment screen and got challan for it as well, but the site got stuck, and it asked me to pay again or pay later, I chose pay later and then completed the filing of ITR.

Will the payment glitch be an issue? if so where should I mention my challan number for fixing it?

Not a CA. But I would assume you revise the return, add the details of the tax that you paid, and resubmit.

For others who face the same situation: what worked for me was that I did a refresh of the browser window. This threw me out of the session, but then I logged in again and resumed the filing, to add the details of the fresh tax paid.