I made a mistake of transferring money from a rollover IRA to Roth IRA, Can I undo the mistake and avoid the taxes

If you moved money from an IRA  to a ROTH then that is called a conversion ... you have until the filing deadline to undo the conversion (in full or any part) ... that is called a recharacterization which is no longer allowed since the change. 

Sorry but the Tax Cuts and Jobs Act (TCJA) prohibits recharacterizing Roth IRA conversions from 2018-2025.   Once converted - it cannot be undone.

I stand  corrected ... see IRS :  https://www.irs.gov/retirement-plans/ira-faqs-recharacterization-of-ira-contributions