I’m using wso2am-4.3.0 and I have disabled OpenAPI validation using the below switch to startup the server in order to import older APIs with validation errors.

-DswaggerRelaxedValidation=true

However, I get the below error in the log when invoking the API and the API fails to respond as well.

ERROR - ServerWorker Error processing GET request for : /xxxx/xxxx. 
java.lang.NullPointerException: null
        at io.swagger.v3.parser.converter.SwaggerConverter.lambda$addProperties$11(SwaggerConverter.java:1268) ~[swagger-parser_2.1.20.wso2v1.jar:?]
        at java.util.LinkedHashMap.forEach(LinkedHashMap.java:684) ~[?:?]
        at io.swagger.v3.parser.converter.SwaggerConverter.addProperties(SwaggerConverter.java:1267) ~[swagger-parser_2.1.20.wso2v1.jar:?]
        at io.swagger.v3.parser.converter.SwaggerConverter.convert(SwaggerConverter.java:1225) ~[swagger-parser_2.1.20.wso2v1.jar:?]
        at io.swagger.v3.parser.converter.SwaggerConverter.convert(SwaggerConverter.java:865) ~[swagger-parser_2.1.20.wso2v1.jar:?]
        at io.swagger.v3.parser.converter.SwaggerConverter.convert(SwaggerConverter.java:635) ~[swagger-parser_2.1.20.wso2v1.jar:?]
        at io.swagger.v3.parser.converter.SwaggerConverter.convert(SwaggerConverter.java:535) ~[swagger-parser_2.1.20.wso2v1.jar:?]
        at io.swagger.v3.parser.converter.SwaggerConverter.convert(SwaggerConverter.java:250) ~[swagger-parser_2.1.20.wso2v1.jar:?]
        at io.swagger.v3.parser.converter.SwaggerConverter.readResult(SwaggerConverter.java:104) ~[swagger-parser_2.1.20.wso2v1.jar:?]
        at io.swagger.v3.parser.converter.SwaggerConverter.readContents(SwaggerConverter.java:99) ~[swagger-parser_2.1.20.wso2v1.jar:?]
        at io.swagger.parser.OpenAPIParser.readContents(OpenAPIParser.java:29) ~[swagger-parser_2.1.20.wso2v1.jar:?]
        at org.wso2.carbon.apimgt.gateway.handlers.common.APIMgtLatencyStatsHandler.setSwaggerToMessageContext_aroundBody8(APIMgtLatencyStatsHandler.java:134) ~[org.wso2.carbon.apimgt.gateway_9.29.120.jar:?]
        at org.wso2.carbon.apimgt.gateway.handlers.common.APIMgtLatencyStatsHandler.setSwaggerToMessageContext(APIMgtLatencyStatsHandler.java:1) ~[org.wso2.carbon.apimgt.gateway_9.29.120.jar:?]
        at org.wso2.carbon.apimgt.gateway.handlers.common.APIMgtLatencyStatsHandler.handleRequest_aroundBody4(APIMgtLatencyStatsHandler.java:98) ~[org.wso2.carbon.apimgt.gateway_9.29.120.jar:?]
        at org.wso2.carbon.apimgt.gateway.handlers.common.APIMgtLatencyStatsHandler.handleRequest(APIMgtLatencyStatsHandler.java:1) ~[org.wso2.carbon.apimgt.gateway_9.29.120.jar:?]
        at org.apache.synapse.api.API.process(API.java:407) ~[synapse-core_4.0.0.wso2v105.jar:4.0.0-wso2v105]
        at org.apache.synapse.api.AbstractApiHandler.apiProcessNonDefaultStrategy(AbstractApiHandler.java:109) ~[synapse-core_4.0.0.wso2v105.jar:4.0.0-wso2v105]
        at org.apache.synapse.api.AbstractApiHandler.identifyAPI(AbstractApiHandler.java:129) ~[synapse-core_4.0.0.wso2v105.jar:4.0.0-wso2v105]
        at org.apache.synapse.api.AbstractApiHandler.dispatchToAPI(AbstractApiHandler.java:61) ~[synapse-core_4.0.0.wso2v105.jar:4.0.0-wso2v105]
        at org.apache.synapse.api.rest.RestRequestHandler.dispatchToAPI(RestRequestHandler.java:90) ~[synapse-core_4.0.0.wso2v105.jar:4.0.0-wso2v105]
        at org.apache.synapse.api.rest.RestRequestHandler.process(RestRequestHandler.java:76) ~[synapse-core_4.0.0.wso2v105.jar:4.0.0-wso2v105]
        at org.apache.synapse.rest.RESTRequestHandler.process(RESTRequestHandler.java:54) ~[synapse-core_4.0.0.wso2v105.jar:4.0.0-wso2v105]
        at org.apache.synapse.core.axis2.Axis2SynapseEnvironment.injectMessage(Axis2SynapseEnvironment.java:350) ~[synapse-core_4.0.0.wso2v105.jar:4.0.0-wso2v105]
        at org.apache.synapse.core.axis2.SynapseMessageReceiver.receive(SynapseMessageReceiver.java:101) ~[synapse-core_4.0.0.wso2v105.jar:4.0.0-wso2v105]
        at org.apache.axis2.engine.AxisEngine.receive(AxisEngine.java:180) ~[axis2_1.6.1.wso2v76.jar:?]
        at org.apache.synapse.transport.passthru.ServerWorker.processNonEntityEnclosingRESTHandler(ServerWorker.java:401) ~[synapse-nhttp-transport_4.0.0.wso2v105.jar:?]
        at org.apache.synapse.transport.passthru.ServerWorker.run(ServerWorker.java:215) ~[synapse-nhttp-transport_4.0.0.wso2v105.jar:?]
        at org.apache.axis2.transport.base.threads.NativeWorkerPool$1.run(NativeWorkerPool.java:172) ~[axis2_1.6.1.wso2v76.jar:?]
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) ~[?:?]
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) ~[?:?]
        at java.lang.Thread.run(Thread.java:834) ~[?:?]

A direction to resolve this issue is much appreciated. Thanks in advance.