Hi,

since yesterday (Jan 6, 2023) I was on 6.47LT since Feb 21, 2021 on my RB1100AHx4.

I didn't dare to upgrade because my Gigaset N510 IP PRO (VOIP DECT Gateway) didn't register any more after upgrading the RB1100 to 6.48.1 (stable).

Yesterday I updated to 6.49.1 (stable) and the phone worked.
Needed a new Winbox then, but that also was fine.

Today I upgraded to 7.6 cause I want to use Wireguard.
Now the VOIP problem is back, it cannot login with provider.

Looks like an on-off-on problem, Microsoft-like ...

Any ideas?

EDIT:
>Yesterday I updated to 6.49.1 (stable) and the phone worked.
Seems that I didnt wait long enough.
After rebooting the N510 the connection works for 1-2 hours, then login is rejected.
So, to make this working again, I have to reset the Rb1100 to 6.47LT or FIND THE CAUSE.
The cause might be some timing issue.

I remember that I tried to contact Mikrotik support 2 yrs ago, bit didnt get a solution.
Maybe a hero is here in the forum

EDIT(2):
I downgraded the RB1100 to 6.48.6LT. It seems to work again. I dont dare to upgrade to the regular "stable" branch.
As a software developer, I suspect there must be a difference between the LT branch and the regular branch in the code.

EDIT(3):
If I want to use Wireguard (that was the only reason to upgrade), I need 7.x.
So I probably wait until a LT version is out, but this will probably never fix this problem.

EDIT(4):
There are 2 things that bother me with Mikrotik:
1. The company's support doesnt take me for serious ( I asked this question 2 yrs ago - and the problem persists)
2. SIP is a unloved step-child at MT, generally (there is no PBX)
3. German distributor FMS needed 3 weeks plus reminder to reply to my mail, which included the offer to PAY for support finding a solution
(and I then didnt even get a reply to that question in my mail)

Conclusion: Even though this old hardware (RB1100) is IMO still great,
though bugs are definitely not more frequent as on other systems which I support
and though newer MT hardware is very competitive,
but then, as the prices went massively up - even compared to the bigger brands,
such a failing support can't motivate to use MT in professional context.

Unfortunately it can be difficult to diagnose SIP issues sometimes. I like to run my own PBX and have found sngrep to be very useful when diagnosing issues. When I don't have access to sngrep I rely on packet captures. Most issues revolve around NAT in my experience but there are a lot of things that can break. If you don't have the expertise to look at packet captures of the SIP interaction or if your provider can't or doesn't help you by looking at them for you then you are basically at the mercy of the hardware and software you use. Testing out different versions and just sticking with what works as long as possible is generally the best course of action in those circumstances.

SIP registration using TCP is normally not a very common problem. Check out if your provider recently has changed the ip address, if you are using a static ip address on the Gigaset or perhaps your dns has cached the old ip address with a long TTL.

I'm also using a Gigaset N510 and most of problems I had in the past was due to NAT that could be resolved using the correct settings for the STUN-server.

One thought, could have ran into DNS bugs in 7.6 as there were many, any wrong response could break SIP. I'd let DNS settle down in V7, unless your PBX is only using IP addresses.