That question was first closed because it is too broad, lacking enough detail to be able to answer. It needs a good network description or diagram, the network device models, the network device configurations, any logs, debugs, etc. You can refer to the Network Engineering Question Checklist for guidance on what should be included.
The reason for closure was changed when you admitted that the routers are MikroTik. On the What topics can I ask about here? page, it has a couple of caveats, including:
hardware that has a paid support option from the manufacturer
(enterprise/provider class products, some small business class
Unfortunately, MikroTik does not offer that, so its devices are off-topic for NE. This Meta answer goes into more detail about that:
The key difference is that vendors who provide paid support for their
own product have a vested interest in the product.
Further, devices with paid support options often also provide better