@DameLyngdoh, on the one hand, should you ask about PEM PKI public key TLS/SSL server certificate and TLS/SSL server private key file format because you want to contribute adding your two cents to solve the symptom at hand, take note of the fact that PEM X.509 public key certificate and private key files format is nothing special and is in form identical with some public key certificate files formats or at least with Base64 alternatives of some public key certificate and private key files formats on Windows. Hence, this and on an intermittently with intermediate interruptions, as a general rule between 20:00 and 07:00 GMT/UTC o'clock, and temporarily operated web server presented Fig.8 obviate that these formats are not a culprit variable in the symptom at hand...
Take note of the fact that I moved a symptom unrelated part of this post to the topic Pell-Mell on Setting Up a Solid Server on Windows.
I am looking forward to hearing of anybody who can reproduce the symptom at hand or who can contribute to solving it.