1) Was there any configuration change related to the LTE vni-0/1xx. If yes, please review what changed. 

2) Was there any subscription change from the SIM Provider perspective? 

3) Run the below command to generate a WWan tech-support and share the below log under /tmp/. 

Sample:

admin@Branch-cli> request interfaces wwan generate-support-logs 

status success 

result Log file generated successfully /tmp/versa-flexvnf-wwan-support-logs-2023-Aug-25-153009.tgz