Rare error when obtaining time via NTP on spresense and LTE board

NTP time retrieval with reference to the sample rarely results in errors.

Error Displayed

ERROR:LTEUDP:337 sendoto() error:22

The source is simple:

timeClient.begin();
timeClient.update();
now=timeClient.getEpochTime();
tm_now = localtime(&now);
timeClient.end();

When this error occurs,
even if you run the above source to get the time again via NTP. The same error occurs repeatedly, and NTP does not have time for a long time.
If there is no error, there is no problem to get the time normally.
It's hard to verify because it's less frequent

If you know how to deal with it, I would appreciate it if you could let me know.