MediaWiki internal error.

Original exception: [12fbd671818b76a4681b0c4b] /index.php?title=Public-Internet_%C4ra&oldid=2147 Wikimedia\Assert\PostconditionException from line 202 of /home/ftp/tbamberg/www/fidopedia.fido.de/htdocs/vendor/wikimedia/assert/src/Assert.php: Postcondition failed: makeTitleSafe() should always return a Title for the text returned by getRootText().
Backtrace:
#0 /home/ftp/tbamberg/www/fidopedia.fido.de/htdocs/includes/Title.php(1986): Wikimedia\Assert\Assert::postcondition()
#1 /home/ftp/tbamberg/www/fidopedia.fido.de/htdocs/includes/skins/Skin.php(480): Title->getRootTitle()
#2 /home/ftp/tbamberg/www/fidopedia.fido.de/htdocs/includes/OutputPage.php(3121): Skin->getPageClasses()
#3 /home/ftp/tbamberg/www/fidopedia.fido.de/htdocs/includes/skins/SkinTemplate.php(391): OutputPage->headElement()
#4 /home/ftp/tbamberg/www/fidopedia.fido.de/htdocs/includes/skins/SkinTemplate.php(127): SkinTemplate->prepareQuickTemplate()
#5 /home/ftp/tbamberg/www/fidopedia.fido.de/htdocs/includes/skins/SkinTemplate.php(144): SkinTemplate->generateHTML()
#6 /home/ftp/tbamberg/www/fidopedia.fido.de/htdocs/includes/OutputPage.php(2615): SkinTemplate->outputPage()
#7 /home/ftp/tbamberg/www/fidopedia.fido.de/htdocs/includes/MediaWiki.php(947): OutputPage->output()
#8 /home/ftp/tbamberg/www/fidopedia.fido.de/htdocs/includes/MediaWiki.php(960): MediaWiki->{closure}()
#9 /home/ftp/tbamberg/www/fidopedia.fido.de/htdocs/includes/MediaWiki.php(543): MediaWiki->main()
#10 /home/ftp/tbamberg/www/fidopedia.fido.de/htdocs/index.php(53): MediaWiki->run()
#11 /home/ftp/tbamberg/www/fidopedia.fido.de/htdocs/index.php(46): wfIndexMain()
#12 {main}

Exception caught inside exception handler: [12fbd671818b76a4681b0c4b] /index.php?title=Public-Internet_%C4ra&oldid=2147 Wikimedia\Assert\PostconditionException from line 202 of /home/ftp/tbamberg/www/fidopedia.fido.de/htdocs/vendor/wikimedia/assert/src/Assert.php: Postcondition failed: makeTitleSafe() should always return a Title for the text returned by getRootText().
Backtrace:
#0 /home/ftp/tbamberg/www/fidopedia.fido.de/htdocs/includes/Title.php(1986): Wikimedia\Assert\Assert::postcondition()
#1 /home/ftp/tbamberg/www/fidopedia.fido.de/htdocs/includes/skins/Skin.php(480): Title->getRootTitle()
#2 /home/ftp/tbamberg/www/fidopedia.fido.de/htdocs/includes/OutputPage.php(3121): Skin->getPageClasses()
#3 /home/ftp/tbamberg/www/fidopedia.fido.de/htdocs/includes/skins/SkinTemplate.php(391): OutputPage->headElement()
#4 /home/ftp/tbamberg/www/fidopedia.fido.de/htdocs/includes/skins/SkinTemplate.php(127): SkinTemplate->prepareQuickTemplate()
#5 /home/ftp/tbamberg/www/fidopedia.fido.de/htdocs/includes/skins/SkinTemplate.php(144): SkinTemplate->generateHTML()
#6 /home/ftp/tbamberg/www/fidopedia.fido.de/htdocs/includes/OutputPage.php(2615): SkinTemplate->outputPage()
#7 /home/ftp/tbamberg/www/fidopedia.fido.de/htdocs/includes/exception/MWExceptionRenderer.php(153): OutputPage->output()
#8 /home/ftp/tbamberg/www/fidopedia.fido.de/htdocs/includes/exception/MWExceptionRenderer.php(65): MWExceptionRenderer::reportHTML()
#9 /home/ftp/tbamberg/www/fidopedia.fido.de/htdocs/includes/exception/MWExceptionHandler.php(106): MWExceptionRenderer::output()
#10 /home/ftp/tbamberg/www/fidopedia.fido.de/htdocs/includes/exception/MWExceptionHandler.php(185): MWExceptionHandler::report()
#11 /home/ftp/tbamberg/www/fidopedia.fido.de/htdocs/includes/MediaWiki.php(576): MWExceptionHandler::handleException()
#12 /home/ftp/tbamberg/www/fidopedia.fido.de/htdocs/index.php(53): MediaWiki->run()
#13 /home/ftp/tbamberg/www/fidopedia.fido.de/htdocs/index.php(46): wfIndexMain()
#14 {main}