This article provides steps to fix the issue of a specific website not loading due to an MTU mismatch in the path.

If the client and server have an MTU of 1500, but an intermediate device has a lower MTU, this could cause issues when loading a website if the website sends packets at the full segment size (i.e MSS 1460) with the DF bit turned on.

A permanent solution to the issue involves isolating the device with a lower MTU size and configuring it with the correct MTU size. If it's not possible to change the MTU on the intermediate device, the same effect can be achieved by configuring TCP MSS clamping on SRX using the command below:

set security flow tcp-mss all-tcp mss <mss-value>

Please refer to the following documentation for a more detailed understanding of TCP MSS clamping: Configuring TCP MSS clamping on SRX devices to avoid unnecessary fragmentation