NiFi suddently stopped working and not able to restart it

[#1]

Hi,

I'm pretty new to NiFi and don't have much experience with it, so it's the reason I'm here.

Yesterday, NiFi was running smoothly and for some reason it stopped working. Every time I tried to start : ./nifi.sh start or any other command it showed me "killed". Later on, I found that java was killed by OOM. Fixed this by restarting server, but it won't start. In the "nifi-bootstrap.log" I found that it's getting shut down due to this error:

I haven't installed any packages, so don't know why it's giving me this error.

Setup:
Ubuntu 20
openjdk 11.0.11
nifi 1.13.2
Connector: mysql-connector-java-8.0.25.jar

What should I check? How to fix this error and start nifi?

Thanks in advance.

[#2]

Hello,

Have you checked the nifi app logs?  What errors you see in nif-app.log. 

[#3]

ERROR [main] o.a.n.c.serialization.FlowFromDOMFactory There was a problem decrypting a sensitive flow configuration value. Check that the nifi.sensitive.props.key value in nifi.properties matches the value used to encrypt the flow.xml.gz file

Was following this guide : https://community.cloudera.com/t5/Support-Questions/Failed-to-connect-node-to-cluster-because-local-...

But stuck witht finding config.zip file

[#4 · Accepted solution]

Can you take a back of up existing flow.xml.gz and remove the flow.xml.gz.  Once you removed the flow.xml.gz try restarting the nifi from the backend.