My neo4j server is automatically stopping and starting, - neo4j

Question

I'm running my neo4j community edition 3.5.5 version with 8GB ram in aws instance.
Initially for few months it ran very fine and got results in millis of time, but now a days it's getting stopping automatically and starting automatically. Sometimes it's not at all starting for hours,even we started it manually also.
Can anyone please help me with this. I'm getting the below logs.
tail -100f /var/log/neo4j/neo4j.log
2019-07-29 13:17:52.570+0000 WARN The client is unauthorized due to authentication failure.
2019-09-04 05:33:52.328+0000 WARN The client is unauthorized due to authentication failure.
2019-10-17 15:18:14.652+0000 INFO Transaction with id 2683388 has been automatically rolled back due to transaction timeout.
nohup: ignoring input
OpenJDK 64-Bit Server VM warning: INFO: os::commit_memory(0x00000006e5400000, 3670016000, 0) failed; error='Cannot allocate memory' (errno=12)
There is insufficient memory for the Java Runtime Environment to continue.
Native memory allocation (mmap) failed to map 3670016000 bytes for committing reserved memory.
An error report file with more information is saved as:
/home/ubuntu/hs_err_pid8965.log
nohup: ignoring input
OpenJDK 64-Bit Server VM warning: INFO: os::commit_memory(0x00000006e5400000, 3670016000, 0) failed; error='Cannot allocate memory' (errno=12)
There is insufficient memory for the Java Runtime Environment to continue.
Native memory allocation (mmap) failed to map 3670016000 bytes for committing reserved memory.
An error report file with more information is saved as:
/home/ubuntu/hs_err_pid9050.log
nohup: ignoring input
OpenJDK 64-Bit Server VM warning: INFO: os::commit_memory(0x00000006e5400000, 3670016000, 0) failed; error='Cannot allocate memory' (errno=12)
2019-10-17 17:14:44.651+0000 INFO Transaction with id 2689294 has been automatically rolled back due to transaction timeout.

Answer 1

this can be because you are running lot of merge operations and dont have proper indices created or try increasing the heap size in config file .