I have several problems with my setup and I am unsure where to begin:

1) I can log in to RB951 using WinBox, but if I try to go to the ip address in a browser, it says this site can't be reached.
2) I cannot ping the router.
3l I cannot backup, or change admin group permissions, I get not permitted (9).
4) Getting to the internet is extremely slow, often timing out, from every computer. But yet I have 750Gbps fiber Optic network.
5) There may be other issues I haven't discovered yet.

This is a fairly new setup, 5 or 6 days. So I am a newbie. Everything seemed to be working fine, and then all of this happened when I began trying to do some port forwarding for my Home Assistant. I did manage to get a backup before all of this behavior started. And it seemed to start all at once.

Please help!!!
Mike

RB951 is a device I used over 10 years ago. Great device, but very outdated especially with your ISP supplied Internet speed.

But...that is not really ontopic...

Can you export the configuration (using termin)?
Remove serial and any other private info and post between code tags by using the </> button.

If not, use Netinstall:
https://wiki.mikrotik.com/Manual:Netinstall
Use the current LTS: 6.49.13

I'm at a high school basketball game right now. I will post later tonight after I get home.

But just out of curiosity, what router would you recommend? I was looking for something to let me set up a few vlans. I have an Orbi mesh system that gives me lots of speed but no vlan tagging. And I am using it as an access point. I guess I never thought about the speed with the RB951. I was just looking for something not too expensive just to check out the brand.

3l I cannot backup, or change admin group permissions, I get not permitted (9).

This item from your symptom list is consistent with several reports of router being compromised (atrackers created another account with full permissions whike permissions of admin account are reduced).

The only proper way out of this is full netinstall (I recommend you to go with latest stable v7 - 7.16.2 right now - or with latest v6 - 6.49.17). And definitely start from default config and change as little as possible. Default firewall config is pretty safe, but it's only too easy to compromise level of security by introducing changes not well thought out.
Of course it's always possible that router was compromised from LAN side (some computer running malware) so if things happen again, check your LAN clients (or restrict access to router management to a dedicated management port).

But just out of curiosity, what router would you recommend?

Have a look at hAP ax2 (or hAP ax3). They have decent CPU built in and are not too expensive (wifi is a bonus, if you don't need it, you can completely disable it which reduces ROS footprint). Definitely come with one of best price/performance ratios in MT fleet.

Of course it's always possible that router was compromised from LAN side (some computer running malware) so if things happen again, check your LAN clients (or restrict access to router management to a dedicated management port).

That would mean a real weak passwd was used or someone in the 'trust' circle (who got the new passwd) is doing funny stuff.

Of course it's always possible that router was compromised from LAN side (some computer running malware) so if things happen again, check your LAN clients (or restrict access to router management to a dedicated management port).

That would mean a real weak passwd was used or someone in the 'trust' circle (who got the new passwd) is doing funny stuff.

What I meant was that default setup blocks management access from WAN and delegates security on LAN side to quality of passwords ... which can be broken much easier than firewall rules (and another user from trust circle is only half a step closer than that). But the point of the quoted text is that one should not forget about (less likely, but not unheard of) breaches from LAN side when investigating reasons for exploit to happen. And I was rather hinting at some malware possibly running on some LAN host which successfully broke admin password.

I know.
And that usually means weak admin passwd.

It could be other reasons as well ... @OP did not start with too many details, e.g. he did not mention exact model (there are 951U and 951G ... not that it matters in this case). Neither he mentioned ROS version and if it's an old one, it may have some vulnerabilities (fixed in last few years) which are normally fenced off from WAN side (if firewall is properly configured) but not from LAN side. And not to forget that really old ROS versions came with less secure default config (ROS upgrades don't touch configuration). And for all these reasons I suggested to start off with netinstall and proceed from defaults ... because ditching decent default and application of same old (possibly flawed) config would re-open the hole which allowed compromise to happen.

Netinstall and starting again from default is seldom a wrong approach

Orbi mesh WIFI? Doubt that will play nice with mikrotik wifi.
My advice is to look at the new hex refresh router for the main router and use oRBi products as APs only.
Its good for an ISP up to 500Mbps, but if you need or anticipate getting a 1 gig connection in the next five years.
the suggestion of the AX3 is a great budget choice, and if budget is not a show stopper the RB5009

The router is a Mikrotik RouterBoard RB951Ui-2nD hAP. It is brand new. The setup is brand new. I have a lan and 2 vlans. One is for IoT devices and one of for guest network. The Netgear Orbi RBR750 is set up as a wifi access point. I have about 50 IoT devices, all with static IP addresses, all accessing the network from the Orbi. I have a Home Assistant that accesses the IoT devices and runs various automation, so I need the devices to have consistent addresses.

I had just finished setting everything up from WinBox and had made a backup. Then I logged in from a browser to the router IP address. I assigned a complex password. I turned on the RB951 wireless and added some firewall port forwards. It was all working fine.

The next morning was when all the problems occurred.

I will post the config file this evening.

The router is a Mikrotik RouterBoard RB951Ui-2nD hAP. It is brand new.

So you bought a new betamax ???

I hope your ISP provides a throughput of less than 200Mbps............

I am confused by this comment. What do you mean by betamax? Isn't that an old vhs tape for tv?

@anav is saying that RB951U is like 15 years old model and if somebody sold it to you as new, then that business has some seriously old stuff on stock. Never mind that it's not officially declared as EoL, it's old never the less.

You still didn't tell us about ROS version running on your RB.

I ordered the RB951 on Amazon, actually. It was running the latest ROS v6. But you all convinced me I needed something more up to date. So I have ordered HAP ax3. As soon as it gets here. I will start again. Thanks for your suggestions.

+1 ....