I tried different options like updating and rebooting the assignment. Neither options are fruitful for submitting the assignment.
Apologies for the error you are facing. Have you tried using any other browser apart from the one you are currently using? Also could you please share the week and exact course under NLP Specialization where you are unable to submit your assignment? Though most of the team is on leave due to holiday season, having this information might help resolve it sooner.
it’s solved now. Thanks for the reply.