The reported issues suggest problems related to network connectivity, remote access, and certificate management:

A. Review VPN throughput: Connectivity issues and the inability to download applications while working remotely may be due to VPN bandwidth or performance issues. Reviewing andoptimizing VPN throughput can help resolve these problems by ensuring that remote users have adequate bandwidth for accessing corporate resources.

F. Validate MDM asset compliance: Mobile Device Management (MDM) systems ensure that mobile endpoints comply with corporate security policies. Validating MDM compliance can help address issues related to the inability to download applications and certificate errors, as non-compliant devices might be blocked from accessing certain resources.

B. Check IPS rules: While important for security, IPS rules are less likely to directly address the connectivity and certificate issues described.

C. Restore static content on the CDN: This action is related to content delivery but does not address VPN or certificate-related issues.

D. Enable secure authentication using NAC: Network Access Control (NAC) enhances security but does not directly address the specific issues described.

E. Implement advanced WAF rules: Web Application Firewalls protect web applications but do not address VPN throughput or mobile device compliance.