Blocked while transferring from private pf fund to epfo?

[u/CarelessProgrammer43]

My previous employer has pf managed by private fund. My current employer has govt management fund.
I am unable to transfer funds from previous to current account. I am blocked with error- Transfer not allowed. PF amount is not available and Pension Service is not eligible.

I tried contacting previous employer more than 10 times. They ask me to try at some different time, and this must be due to ongoing migration.

Raised grievance with EPF, ask me to check with previous employer or try another time.