Try using Google as a TLS time source

beaglebone.txt

@@ -1018,7 +1018,7 @@ Add the following:
 #+BEGIN_SRC: bash
 #!/bin/bash
 
-TIMESOURCE=www.ptb.de
+TIMESOURCE=google.com
 LOGFILE=/var/log/tlsdate.log
 DATE_BEFORE=$(date)
 YEAR_BEFORE=$(echo $DATE_BEFORE | awk -F ' ' '{print $6}')