Getting fluctuations in temperature during npt run

GROMACS version:2021.2
GROMACS modification: Yes/No
Dear users,
I am simulating a polymer using gromos forcefield parameters. After minimization, i ran canonical ensemble (NVT). During NVT i got a temperature fluctuation of ± 5K about its average value which is 425 K. Now when I switch to the NPT ensemble, my temperature fluctioans are increasing. During NPT temperature is fluctuating ±50 K about its average value which is 425. I did ibserve the system for 2ns.
Please help me to minimize the temperature fluctuations of my system.
tempearture_npt

What thermostat settings did you use in each phase of the simulations? Methods like V-rescale have intrinsically much smaller fluctuations than, e.g. Nosé-Hoover, and you can modulate the magnitude of fluctuations with τT for both.

Thank you for your reply. I have changed the thermostat from Nose-Hoover to V-rescale and it worked. Now the temperature fluctuation is less.