I have same issue. 

cert issuer.crt expired, ho wcan i renew it manually? (without reinstall kubernetes) 

Any IDEA ?

Same issue. Any solution?

I think I found it the best way for me: reinstall ifs-ingress :

.\main.ps1 -resource 'INGRESS'

it works for me.

Not working

2023-11-28 15:04:14.53   DVKORA4 Start Main
2023-11-28 15:04:14.55   DVKORA4 Action Type :
2023-11-28 15:04:14.56   DVKORA4 Resource Type : INGRESS
2023-11-28 15:04:14.58   DVKORA4 Start Download-IfsIngress
2023-11-28 15:04:14.60   DVKORA4 Downloading IfsIngress.......
"ifscloud" has been added to your repositories
Hang tight while we grab the latest from your chart repositories...
...Successfully got an update from the "ifscloud" chart repository
Update Complete. ⎈Happy Helming!⎈
2023-11-28 15:04:16.10   DVKORA4 IfsIngress downloaded successfully
2023-11-28 15:04:16.10   DVKORA4 Stop Download-IfsIngress
2023-11-28 15:04:16.11   DVKORA4 Start ImagePullSecret-IfsIngress
2023-11-28 15:04:16.14   DVKORA4 Creating ImagePullSecret ifs-ingress namespace.......
"ifscloud" has been added to your repositories
Hang tight while we grab the latest from your chart repositories...
...Successfully got an update from the "ifscloud" chart repository
Update Complete. ⎈Happy Helming!⎈
Error: Kubernetes cluster unreachable: Get "https://10.26.41.117:16443/version": x509: certificate has expired or is not
 yet valid: current time 2023-11-28T15:04:17+01:00 is after 2023-11-28T11:50:19Z
2023-11-28 15:04:17.07   DVKORA4 IFSIngress ImagePullSecret created successfully
2023-11-28 15:04:17.07   DVKORA4 Stop ImagePullSecret-IfsIngress
2023-11-28 15:04:17.07   DVKORA4 Start Install-IfsIngress
2023-11-28 15:04:17.07   DVKORA4 Installing ifs-ingress.......
Your certificate has been saved in D:\ifsremote\ifsroot\utils\..\config\certs/ca.crt.
Your private key has been saved in D:\ifsremote\ifsroot\utils\..\config\certs/ca.key.
Your certificate has been saved in D:\ifsremote\ifsroot\utils\..\config\certs/issuer.crt.
Your private key has been saved in D:\ifsremote\ifsroot\utils\..\config\certs/issuer.key.
Error: Kubernetes cluster unreachable: Get "https://10.26.41.117:16443/version": x509: certificate has expired or is not
 yet valid: current time 2023-11-28T15:04:17+01:00 is after 2023-11-28T11:50:19Z
2023-11-28 15:04:17.71   DVKORA4 ifs-ingress installed successfully
2023-11-28 15:04:17.71   DVKORA4 Stop Install-IfsIngress

If not working, the only way is reinstall kubernetes + ifs cloud remote. To avoid certificate expiration,  you should install at least yearly a new IFS update, or reinstall ifs-ingress a couple days before certificate will expire. I don't  know another way.