I installed your module on my test system. Testing the link http://ahnentest.hartenthaler.eu/index.php?route=/cron/telegram results in an error (API key replaced by xxx):
file_get_contents(https://api.telegram.org/botxxx/sendMessage): Failed to open stream: HTTP request failed! HTTP/1.1 400 Bad Request
…/modules_v4/telegram/CronJob.php:244
#0 [internal function]: Fisharebest\Webtrees\Http\Middleware\ErrorHandler->errorHandler()
#1 …/modules_v4/telegram/CronJob.php(244): file_get_contents()
#2 …/modules_v4/telegram/CronJob.php(87): Tywed\Webtrees\Module\Telegram\CronJob->sendTelegramMessage()
#3 …/app/Http/Middleware/RequestHandler.php(52): Tywed\Webtrees\Module\Telegram\CronJob->handle()
I installed your module on my test system. Testing the link http://ahnentest.hartenthaler.eu/index.php?route=/cron/telegram results in an error (API key replaced by xxx):