What should I do if developers keep asking me to follow-up with their technical requests?

Developers usually think project managers should help them follow up to get the technical approvals, including new system access or security approval. The impression is incorrect because PMO should help the project manager focus on the project execution, not technical details. Therefore, in the PMO playbook, it's a best practice to include the following guideline: 

PMO will manage the project from a scheduling and deliverable perspective but DOES NOT engage in detailed requirement clarification, technical design decisions, solution task planning, testing content and execution discussions, technical risk mitigation, issue resolution, user training, APS transition and technical approvals including information security, network, platform, performance, and CR approvals.

However, PMO can perform escalation as part of it stakeholder management when there is unexpected delay of the request.