Forwarded vanity domains, suddenly resolving to 404 with appended URL's ending in random 5 characters

[SS.Digital]

We have several vanity domains that forward to various pages on our primary domain.
e.g. www.vanity.com (301)--> www.mydomain.com/sub-page (200)

These forwards have been in place for months or even years and have worked fine.  As of yesterday, we have seen the following problem.  We have made no changes in the forwarding settings.

Now, inconsistently, they sometimes resolve and sometimes they do not.  When we load the vanity URL with Chrome Dev Tools (Network Pane) open, it shows the following redirect chains, where xxxxx represents a random 5 character string of lower and upper case letters.  (e.g. VGuTD)

EXAMPLE:
www.vanity.com                                  (302, Found) -->
www.vanity.com/xxxxx                        (302, Found) -->
www.vanity.com/xxxxx                        (302, Found) -->
www.vanity.com/xxxxx/xxxxx               (302, Found) -->
www.mydomain.com/sub-page/xxxxx (404, Not Found)

This is just one example, the amount of redirects, vary wildly.  Sometimes there is only 1 redirect, sometimes there are as many as 5.

Sometimes the request will ultimately resolve on the correct mydomain.com/sub-page, but usually it does not (as in the example above).

We have cross-checked across every browser, device, private/non-private, cookies cleared, on and off of our network etc...   This leads us to believe that it is not at the device or host level.

Our Registrar is Godaddy.  They have not encountered this issue before, and have no idea what this 5 character string is from.  I tend to believe them because per our analytics, we have determined that this problem only started yesterday.

Our primary question is, has anybody else encountered this problem either in the last couple days, or at any time in the past?  We have come up with a solution that works to alleviate the problem, but to implement it across hundreds of vanity domains will take us an inordinate amount of time.  Really hoping to fix the cause of the problem instead of just treating the symptom.

[SS.Digital]

It looks like this is a GoDaddy specific issue that many others are experiencing:

https://www.godaddy.com/community/Managing-Domains/My-domain-name-not-resolving-correctly-6-random-characters-are/td-p/60782

Although, at the time of this writing GoDaddy has not offered an explanation nor resolution. However, a workaround may be forwarding the domain with a query string appended, which in turn, appends the random six characters to the query string, instead of creating a url segment that the CMS interprets as a non-existent page and throws a 404.

For example, consider:

www.vanity.com -> www.primary.com?utm_source=forward

The GoDaddy issue should then resolve with via:

www.primary.com?utm_source=forwardxxxxxx

Alternatively, the fowarding can be accomplished from the reverse angle, if you have access to the hosting account of the primary domain by adding a forwarded domain from something like cPanel or Plesk that points the primary domain name and then updating the GoDaddy A record to point to the primary domain's IP Address (and remove any GoDaddy forwarding).

Or migrate from GoDaddy!

[MikeTek]

That's a very strange behavior I have not seen before (and I've had plenty of experience with GoDaddy and their domain forwarding).

The query workaround is interesting/clever - but I'd also be inclined to want to sort out why this is happening at all and stop it vs reworking all the domain forwards around this symptom.

Have you contacted GoDaddy's shared hosting support? I'm not the biggest GoDaddy fan overall, but their tech support team can be quite helpful in tracking issues like this down.

[SS.Digital]

Yes, we have contacted GoDaddy several times.

GoDaddy has insisted it is not their problem and they do not have any advice to resolve this issue. GoDaddy support said there can be strange behavior when forward and masking. We tested removing the masking, but it did not make a difference. Nor does 301 vs. 302 redirecting. I understand the latter should not be used as a workaround as these responses have different meanings, but we did test (which also made no difference).

Check this link for more details:

https://www.godaddy.com/community/Managing-Domains/My-domain-name-not-resolving-correctly-6-random-characters-are/m-p/64440#M16148

Others are experiencing the same issue and somewhere in the thread it was stated that GoDaddy recently rolled out a new system which likely created this issue. We can trace the issue beginning in late August 2017 via Google Analytics, Search Console 404s and testing via Chrome Dev Tools (Network pane with Preserve log checked).

We would also like to understand why in order to address the root cause, instead of using a workaround. This is significant issue. Unfortunately, GoDaddy is not handling the issue professionally and will impact our future business decisions involving GoDaddy.