Received JWT authentication from unknown host

[sahan 2018]

I get this error when I try to install my plugin in JIRA Cloud. The strange is, it was working fine couple of days back however now it throws this error when ever my plugin tries to communicate with Jira instance. 

During a google search, I saw that there is something related to licencing which can cause this issue. That is, set "enableLicencing : true" in descriptor file. Is this setting mandatory?

Does anyone have any idea of this error? Much appreciate your help on this.

2018-03-14 14:30:17 [WARN] [c.a.c.s.i.a.j.JwtAuthenticationFilter] Received JWT authentication from unknown host (520bbe37-7ca4-3c52-b84f-e9ad7851e3be), but allowing anyway.

Further stack:

2018-03-14 14:37:02 [ERROR] [o.a.c.c.C.[.[.[.[dispatcherServlet]] Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.springframework.web.client.HttpClientErrorException: 400 Bad Request] with root causeorg.springframework.web.client.HttpClientErrorException: 400 Bad Request        at org.springframework.web.client.DefaultResponseErrorHandler.handleError(DefaultResponseErrorHandler.java:91)        at org.springframework.web.client.RestTemplate.handleResponse(RestTemplate.java:667)        at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:620)        at org.springframework.web.client.RestTemplate.execute(RestTemplate.java:580)        at org.springframework.web.client.RestTemplate.exchange(RestTemplate.java:526)        at com.atlassian.connect.spring.internal.request.oauth2.JwtBearerAccessTokenProvider.obtainAccessToken(JwtBearerAccessTokenProvider.java:65)        at org.springframework.security.oauth2.client.OAuth2RestTemplate.acquireAccessToken(OAuth2RestTemplate.java:221)        at org.springframework.security.oauth2.client.OAuth2RestTemplate.getAccessToken(OAuth2RestTemplate.java:173)        at org.springframework.security.oauth2.client.OAuth2RestTemplate.createRequest(OAuth2RestTemplate.java:105)        at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:615)        at org.springframework.security.oauth2.client.OAuth2RestTemplate.doExecute(OAuth2RestTemplate.java:128)        at org.springframework.web.client.RestTemplate.execute(RestTemplate.java:580)        at org.springframework.web.client.RestTemplate.getForEntity(RestTemplate.java:312)        at