Will it, realistically, ever happen?

If you are using the major providers, you are very unlikely to run into this problem. But it is still possible, And after all, Google dropped their Google+ SSO in 2019 with no waning at all to the industry¹, and it broke 1000's of sites SSO that had been relying on it. It broke us for several hours too. If it does happen to your provider it will be such a huge headache for our customers that we have put a plan in place, just in case.

Essentially, if this were to happen, you will need to get your users over to a new SSO provider 'quickly'. In the Google case above, we were able to respond with a fix within hours, in that case the other Google SSO was able to carry on without any other changes other than what we had to make to our LoginHub service.

So, where the change is effectively 'taken over' by another company or service where your data is retained, our history and our plan is to quickly do the conversion for you, or at least as much as we possibly can, so that you will not be inconvenienced, and we consider that part of the cost of SMA.

If the service is going away with no way to convert to another one, you can, with all LoginHub licenses: Switch your license to one of the same price or lower at no charge and if the provider you are changing to is more expensive, you can pay the difference to switch your license to the more expensive one.

There will also likely be support costs (hourly) associated with switching if you need assistance setting up a provider you haven't previously used.

If this happens, you are going to have to do some work. You will need to setup with your new SSO Advanced or Premium provider. In LoginHub you will need to setup your groups and roles and any custom features. Depending on how much you are relying on custom features of your provider (especially the Enterprise SSO providers) this may be difficult. If your provider quit with very little warning you may decide to temporarily do it in a simplistic way to 'get going quickly, then go back and set it fully up later, but if your provider gave you sufficient warning, you will likely want to set it up 'correctly' with your new provider.

Obviously, since this is SSO, you have other products that are also going to be drastically affected, and the work to create your users in the new SSO will depend largely on how much warning your SSO provider gives you.

You will have to, with your new SSO, setup all your new users. Yes this will be difficult if you have no access to the old SSO user list and details, you may want to start with MC to look at the users there and set all those ones up first on the assumption that, if they have logged in before, they are the most likely to want to login soon..

From LoginHub, you will go in and use the 'migrate' features to allow users to 'migrate' from the old SSO to the new SSO. This may be a problem, because you need to have an administrator login. This will require someone with very high level access to your data to make a change directly in the database to give one administrator the ability to login with the new SSO provider, you will likely want to talk to our support staff to do this for you.

You will want to make it easy for users to convert over, our normal recommendation is that you allow email address to be used to link from the old to the new. This should dramatically reduce your administration efforts during this tough time.

Then, when they login with the new SSO, they will get permissions from your new SSO provider and as long as their email address is allowed to be used to match, anyone who has the same email address in both SSO providers will be able to easily link up with the new provider. If they can't, they will have no real way to change their email address, so this needs to be thought through in your process.