Too many open files - Mongo 4.2

Hi Folks

This mongo instance has crashed a few more times since, with the below in the logs the latest time. Any other troubleshooting advice?

**2020-09-30T11:05:40.172+0000 I  ACCESS   [conn94647] Successfully authenticated as principal DbUser on admin from client 13.0.1.189:34528
2020-09-30T11:05:40.172+0000 I  ACCESS   [conn94559] Successfully authenticated as principal DbUser on admin from client 13.0.1.189:34356
2020-09-30T11:05:40.180+0000 I  ACCESS   [conn94566] Successfully authenticated as principal DbUser on admin from client 13.0.1.189:34358
2020-09-30T11:05:40.181+0000 E  -        [conn95032] cannot open /dev/urandom Too many open files
2020-09-30T11:05:40.181+0000 F  -        [conn95032] Fatal Assertion 28839 at src/mongo/platform/random.cpp 159
2020-09-30T11:05:40.183+0000 F  -        [conn95032]

***aborting after fassert() failure


2020-09-30T11:05:40.183+0000 E  -        [conn95028] cannot open /dev/urandom Too many open files
2020-09-30T11:05:40.183+0000 F  -        [conn95028] Fatal Assertion 28839 at src/mongo/platform/random.cpp 159
2020-09-30T11:05:40.183+0000 F  -        [conn95028]

***aborting after fassert() failure


2020-09-30T11:05:40.183+0000 E  -        [conn95031] cannot open /dev/urandom Too many open files
2020-09-30T11:05:40.183+0000 F  -        [conn95031] Fatal Assertion 28839 at src/mongo/platform/random.cpp 159
2020-09-30T11:05:40.183+0000 F  -        [conn95031]

***aborting after fassert() failure


2020-09-30T11:05:40.183+0000 E  -        [conn95025] cannot open /dev/urandom Too many open files
2020-09-30T11:05:40.183+0000 F  -        [conn95025] Fatal Assertion 28839 at src/mongo/platform/random.cpp 159
2020-09-30T11:05:40.183+0000 F  -        [conn95025]

***aborting after fassert() failure**

Cheers,
Niamh