My Phone Displays says 'no access to network'. What to repair?

On the top of my phones display it's shown 'no access to network' - what do i have to repair that access would be possible again? That was never before a problem (i'm using the phone for 10 years). Thank you!

crwdns2934089:0crwdne2934089:0 crwdns2934093:0crwdne2934093:0

crwdns2934109:0crwdne2934109:0

crwdns2889612:0crwdne2889612:0 0
crwdns2934285:0crwdne2934285:0