how to fix openssl random generator error?

we have a problem with openssl 1.1.1n (that compiled by nginx --with-openssl flag), sometimes we see some errors in nginx logs, but we can not regenerate to debug, errors content is : random number generator:rand_pool_add:internal error anyone have an idea?

rand_pool_add() returns 0 in the following cases: 1.If there's an error, i.e. too much data is added for the given pool. 2.If there isn't enough entropy.