Trying to rename category gives error.

Tried to rename a sub category (Counter Offset) and got this:

Something went wrong: [DwE500REX]

java.lang.RuntimeException: Cannot save 2 permissions, would result in 308 permissions in total, but 200 is max [TyEMNYPERMS]
	at com.debiki.core.Prelude$.die(Prelude.scala:160)
	at com.debiki.core.Prelude$.dieIf(Prelude.scala:174)
	at debiki.dao.CategoriesDao.addRemovePermsOnCategory(CategoriesDao.scala:807)
	at debiki.dao.CategoriesDao.$anonfun$editCategory$1(CategoriesDao.scala:613)
	at debiki.dao.SiteDao.$anonfun$readWriteTransaction$2(SiteDao.scala:262)
	at com.debiki.core.DbDao2.readWriteSiteTransaction(DbDao2.scala:67)
	at debiki.dao.SiteDao.$anonfun$readWriteTransaction$1(SiteDao.scala:262)
	at debiki.dao.SiteDao$.synchronizeOnSiteId(SiteDao.scala:647)
	at debiki.dao.SiteDao.readWriteTransaction(SiteDao.scala:261)
	at debiki.dao.CategoriesDao.editCategory(CategoriesDao.scala:589)
	at debiki.dao.CategoriesDao.editCategory$(CategoriesDao.scala:587)
	at debiki.dao.SiteDao.editCategory(SiteDao.scala:91)
	at controllers.ForumController.$anonfun$saveCategory$1(ForumController.scala:205)
	at scala.Function1.$anonfun$andThen$1(Function1.scala:57)
	at ed.server.http.PlainApiActions$$anon$1.runBlockIfAuthOk(PlainApiActions.scala:573)
	at ed.server.http.PlainApiActions$$anon$1.invokeBlockAuthViaCookie(PlainApiActions.scala:384)
	at ed.server.http.PlainApiActions$$anon$1.invokeBlockImpl(PlainApiActions.scala:235)
	at ed.server.http.PlainApiActions$$anon$1.invokeBlock(PlainApiActions.scala:121)
	at ed.server.http.PlainApiActions$$anon$1.invokeBlock(PlainApiActions.scala:94)
	at play.api.mvc.ActionBuilder$$anon$9.apply(Action.scala:379)
	at ed.server.http.PlainApiActions$$anon$1.$anonfun$composeAction$1(PlainApiActions.scala:108)
	at ed.server.http.SafeActions$ExceptionAction$.invokeBlock(SafeActions.scala:117)
	at ed.server.http.SafeActions$ExceptionAction$.invokeBlock(SafeActions.scala:83)
	at play.api.mvc.ActionBuilder$$anon$9.apply(Action.scala:379)
	at play.api.mvc.Action.$anonfun$apply$4(Action.scala:82)
	at play.api.libs.streams.StrictAccumulator.$anonfun$mapFuture$4(Accumulator.scala:168)
	at scala.util.Try$.apply(Try.scala:213)
	at play.api.libs.streams.StrictAccumulator.$anonfun$mapFuture$3(Accumulator.scala:168)
	at scala.Function1.$anonfun$andThen$1(Function1.scala:57)
	at scala.Function1.$anonfun$andThen$1(Function1.scala:57)
	at play.api.libs.streams.StrictAccumulator.run(Accumulator.scala:200)
	at play.core.server.AkkaHttpServer.$anonfun$runAction$4(AkkaHttpServer.scala:417)
	at akka.http.scaladsl.util.FastFuture$.strictTransform$1(FastFuture.scala:41)
	at akka.http.scaladsl.util.FastFuture$.$anonfun$transformWith$3(FastFuture.scala:51)
	at scala.concurrent.impl.CallbackRunnable.run(Promise.scala:64)
	at akka.dispatch.BatchingExecutor$AbstractBatch.processBatch(BatchingExecutor.scala:56)
	at akka.dispatch.BatchingExecutor$BlockableBatch.$anonfun$run$1(BatchingExecutor.scala:93)
	at scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.java:23)
	at scala.concurrent.BlockContext$.withBlockContext(BlockContext.scala:85)
	at akka.dispatch.BatchingExecutor$BlockableBatch.run(BatchingExecutor.scala:93)
	at akka.dispatch.TaskInvocation.run(AbstractDispatcher.scala:48)
	at akka.dispatch.ForkJoinExecutorConfigurator$AkkaForkJoinTask.exec(ForkJoinExecutorConfigurator.scala:48)
	at java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:289)
	at java.util.concurrent.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1056)
	at java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1692)
	at java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:157)