Add certificat for webserver : Unable to decode the PEM-encoded private key

I try to add a certificat for HTTPS ignition webserver.
I have the following error.
Any idea for the cause ?

Do I need to open it with keystoreExplorer and export in another format ?

SslConfigRoutes	06Nov2025 16:41:36	Unable to decode the PEM-encoded private key
java.lang.Exception: Expected the object to be one of PrivateKeyInfo, PEMKeyPair, PKCS8EncryptedPrivateKeyInfo, or PEMEncryptedKeyPair but got null

at com.inductiveautomation.ignition.gateway.ssl.PrivateKeyUtil.readPrivateKeyInfo(PrivateKeyUtil.java:191)

at com.inductiveautomation.ignition.gateway.ssl.PrivateKeyUtil.readPrivateKey(PrivateKeyUtil.java:214)

at com.inductiveautomation.ignition.gateway.ssl.SslConfigRoutes.parseAndValidatePrivateKey(SslConfigRoutes.java:549)

at com.inductiveautomation.ignition.gateway.dataroutes.Route.service(Route.java:284)

at com.inductiveautomation.ignition.gateway.dataroutes.RouteGroupImpl.service(RouteGroupImpl.java:66)

at com.inductiveautomation.ignition.gateway.dataroutes.RouteGroupCollectionServlet.serviceInternal(RouteGroupCollectionServlet.java:59)

at com.inductiveautomation.ignition.gateway.dataroutes.AbstractRouteGroupServlet.service(AbstractRouteGroupServlet.java:38)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:590)

at org.eclipse.jetty.ee8.servlet.ServletHolder$NotAsync.service(ServletHolder.java:1151)

at org.eclipse.jetty.ee8.servlet.ServletHolder.handle(ServletHolder.java:640)

at org.eclipse.jetty.ee8.servlet.ServletHandler$ChainEnd.doFilter(ServletHandler.java:1374)

at com.inductiveautomation.catapult.filters.GatewayFilter.doFilter(GatewayFilter.java:73)

at javax.servlet.http.HttpFilter.doFilter(HttpFilter.java:97)

at org.eclipse.jetty.ee8.servlet.FilterHolder.doFilter(FilterHolder.java:177)

at org.eclipse.jetty.ee8.servlet.ServletHandler$Chain.doFilter(ServletHandler.java:1348)

at org.eclipse.jetty.ee8.servlet.ServletHandler.doHandle(ServletHandler.java:454)

at org.eclipse.jetty.ee8.nested.ScopedHandler.handle(ScopedHandler.java:119)

at org.eclipse.jetty.ee8.security.SecurityHandler.handle(SecurityHandler.java:497)

at org.eclipse.jetty.ee8.nested.HandlerWrapper.handle(HandlerWrapper.java:108)

at org.eclipse.jetty.ee8.nested.ScopedHandler.nextHandle(ScopedHandler.java:183)

at org.eclipse.jetty.ee8.nested.SessionHandler.doHandle(SessionHandler.java:519)

at org.eclipse.jetty.ee8.nested.ScopedHandler.nextHandle(ScopedHandler.java:181)

at org.eclipse.jetty.ee8.nested.ContextHandler.doHandle(ContextHandler.java:885)

at org.eclipse.jetty.ee8.nested.ScopedHandler.nextScope(ScopedHandler.java:152)

at org.eclipse.jetty.ee8.servlet.ServletHandler.doScope(ServletHandler.java:423)

at org.eclipse.jetty.ee8.nested.ScopedHandler.nextScope(ScopedHandler.java:150)

at org.eclipse.jetty.ee8.nested.SessionHandler.doScope(SessionHandler.java:503)

at org.eclipse.jetty.ee8.nested.ScopedHandler.nextScope(ScopedHandler.java:150)

at org.eclipse.jetty.ee8.nested.ContextHandler.doScope(ContextHandler.java:830)

at org.eclipse.jetty.ee8.nested.ScopedHandler.handle(ScopedHandler.java:117)

at org.eclipse.jetty.ee8.nested.ContextHandler.handle(ContextHandler.java:1443)

at org.eclipse.jetty.ee8.nested.HttpChannel$RequestDispatchable.dispatch(HttpChannel.java:1289)

at org.eclipse.jetty.ee8.nested.HttpChannel.dispatch(HttpChannel.java:616)

at org.eclipse.jetty.ee8.nested.HttpChannel.handle(HttpChannel.java:459)

at org.eclipse.jetty.ee8.nested.ContextHandler$CoreContextHandler$CoreToNestedHandler.handle(ContextHandler.java:2450)

at org.eclipse.jetty.server.handler.ContextHandler.handle(ContextHandler.java:1064)

at org.eclipse.jetty.rewrite.handler.RewriteHandler$LastRuleHandler.handle(RewriteHandler.java:159)

at org.eclipse.jetty.rewrite.handler.Rule$Handler.handle(Rule.java:108)

at org.eclipse.jetty.rewrite.handler.HeaderPatternRule$1.handle(HeaderPatternRule.java:89)

at org.eclipse.jetty.rewrite.handler.Rule$Handler.handle(Rule.java:108)

at org.eclipse.jetty.rewrite.handler.HeaderPatternRule$1.handle(HeaderPatternRule.java:89)

at org.eclipse.jetty.rewrite.handler.Rule$Handler.handle(Rule.java:108)

at org.eclipse.jetty.rewrite.handler.HeaderPatternRule$1.handle(HeaderPatternRule.java:89)

at org.eclipse.jetty.rewrite.handler.Rule$Handler.handle(Rule.java:108)

at org.eclipse.jetty.rewrite.handler.HeaderPatternRule$1.handle(HeaderPatternRule.java:89)

at org.eclipse.jetty.rewrite.handler.Rule$Handler.handle(Rule.java:108)

at org.eclipse.jetty.rewrite.handler.RewriteHandler.handle(RewriteHandler.java:143)

at org.eclipse.jetty.server.Handler$Sequence.handle(Handler.java:805)

at org.eclipse.jetty.server.Handler$Sequence.handle(Handler.java:805)

at org.eclipse.jetty.server.Server.handle(Server.java:182)

at org.eclipse.jetty.server.internal.HttpChannelState$HandlerInvoker.run(HttpChannelState.java:662)

at org.eclipse.jetty.server.internal.HttpConnection.onFillable(HttpConnection.java:416)

at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:322)

at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:99)

at org.eclipse.jetty.io.SelectableChannelEndPoint$1.run(SelectableChannelEndPoint.java:53)

at org.eclipse.jetty.util.thread.strategy.AdaptiveExecutionStrategy.runTask(AdaptiveExecutionStrategy.java:480)

at org.eclipse.jetty.util.thread.strategy.AdaptiveExecutionStrategy.consumeTask(AdaptiveExecutionStrategy.java:443)

at org.eclipse.jetty.util.thread.strategy.AdaptiveExecutionStrategy.tryProduce(AdaptiveExecutionStrategy.java:293)

at org.eclipse.jetty.util.thread.strategy.AdaptiveExecutionStrategy.run(AdaptiveExecutionStrategy.java:201)

at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run(ReservedThreadExecutor.java:311)

at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:979)

at org.eclipse.jetty.util.thread.QueuedThreadPool$Runner.doRunJob(QueuedThreadPool.java:1209)

at org.eclipse.jetty.util.thread.QueuedThreadPool$Runner.run(QueuedThreadPool.java:1164)