"no problem" or "no problems"

English as a Second Language English Vocabulary, Grammar and Idioms
1

Dear friend
Is it right to say “no problem” or no “problems”.

For eg 1.“I forgot to bring the admit card”
“No problem or problems”.

nick

2

No problem. There is no need to use “problems”.

3

This is what I’ve found in Longman Dictionary:
no problem
spoken
a) used to say that you are happy to do something or for someone else to do something
‘Can I bring a friend?’ ‘Sure, no problem.’
b) used after someone has said thank you or said that they are sorry
‘Thanks for all your help.’ ‘No problem!’