I tried to use my old sim after a few days of travel but it shows no sim or invalid sim. How can I get it working?

[Windows Central Question]

tried to use my old sim after a few days of travel but it shows no sim or invalid sim

after travelling for 15 days outside India I tried to use my old sim but it shows no sim or invalid sim only emergency calls if my mobile operator supports

 

[Harrie-S]

This could be a phone or SIM card issue.
Please check if your SIM tray is "dirty".
Please try another SIM to see if this works.
If another SIM works but your old SIM not please contact your provider for a new SIM.
If no SIM card works and there is no "dirt" in the SIM tray a soft or hard reset could help if it is a software issue. If both do not work you have a "hardware" problem and a visit to a repair shop may be needed.

Good luck