what is the reason for it ? if you can tell me it .
It isn’t really abnormal to have some time pass without seeing new things. Once in awhile Fiverr doesn’t renew them in the usual pattern. They take care not to release them at the same time every day because it gives unfair advantage to people in some time zones, so they release new ones on a semi-sporadic schedule from what I can tell. Plus, occasionally the request system has a glitch and fails to re-populate in part or all categories.
Since you are also only selling in one category and it’s a very common one that is easy to find in search, there are sometimes no new ones at all for a few days. Buyer requests have a tendency to populate faster with unusual requests that are difficult to find in search.