D-Link AC1900 User Manual page 136

Section 7 - Troubleshooting
3. Why can't I connect to certain sites or send and receive emails when connecting through my router?
If you are having a problem sending or receiving email, or connecting to secure sites such as eBay, banking sites, and Hotmail,
we suggest lowering the MTU in increments of ten (Ex. 1492, 1482, 1472, etc).
To nd the proper MTU Size, you'll have to do a special ping of the destination you're trying to go to. A destination could be
another computer, or a URL.
Start and then click Run.
command (Windows® NT, 2000, XP, Vista®, and 7 users type in cmd) and
press (or click OK).
ping [url] [-f] [-l] [MTU value]
Example: ping yahoo.com -f -l 1472
D-Link DIR-878 User Manual 132