Slow Internet speed

I just changed my internet speed from ETTH 25 Mb (Microwave) to FTTH 300 Mb (Fiber) the only difference was that untangle used to do the dial-up for the connection and it all worked out great.

after i installed the fiber, my provider gave me a Fiber modem router which cannot be bridged so i had to use their modem for the dial up.
When i connect my laptop directly to their modem i get the full 300 Mb speed, but when i connect it through untangle as the DHCP server i only get 17 Mb.

please note the below settings of untangle

Attachment 10645
Attachment 10646

i have also disabled webfilter, application control and bandwidth control.

i dont know what im doing wrong

Did you check qos?

I am a noob for sure and need some help. I am having an issue with my speeds as well. I am only getting 400Mbs download speed and 70 Mbs upload speed out of my firewall. I have Gigabit internet and it is fiber. I do not have QoS enabled. If I perform a reboot on my machine it goes up to about 500 Mbs download and 930 Mbs upload. Any ideas would be great. My specs for the device I am running untangle on is as follows:

CPU Type: Intel(R) Xeon(R) CPU X3440 @ 2.53GHz
Architecture: amd64
Memory: 8.36 GB
Disk: 88.12 GB