com.atlassian.jira.workflow.WorkflowException (GH v 6.2)

When i click on "View issues in issue navigator" in Agile / GH board, it shows me following error

"Lexing failed on line: 7, column: 1, while reading '<', no possible valid JSON value or punctuation could be recognized."

Also after wards if i click on , isues link available in JIRA it shows me a error message: "The JIRA server could not be contacted. This may be a temporary glitch or the server may be down."

This time i also see following error in the logs catalina.out log file:

506x44265x1 mtwyf1 10.178.46.230,127.0.0.1 /rest/api/1.0/menus/find_link [common.error.jersey.ThrowableExceptionMapper] Uncaught exception thrown by REST service

groovy.json.JsonException: Lexing failed on line: 7, column: 1, while reading '<', no possible valid JSON value or punctuation could be recognized.

at groovy.json.JsonLexer.nextToken(JsonLexer.java:83)

at groovy.json.JsonSlurper.parse(JsonSlurper.java:73)

at groovy.json.JsonSlurper.parseText(JsonSlurper.java:59)

at groovy.json.JsonSlurper$parseText.call(Unknown Source)

at com.onresolve.jira.groovy.jql.IssuesInSprint.execMethod(script13729186275822048495194.groovy:117)

at com.onresolve.jira.groovy.jql.IssuesInSprint.this$3$execMethod(script13729186275822048495194.groovy)

at sun.reflect.GeneratedMethodAccessor1850.invoke(Unknown Source)

at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)

at java.lang.reflect.Method.invoke(Unknown Source)

this is happening every time I follow these two steps, if i login and click on Issues link, it brings up all options properly..

Can you look into this issue..