Domain proton.me on blacklist

My district was testing our clubs' responeses to website inquiries and we initially were using a Proton email address (domain @proton.me). When most of our inquiries got immediately blocked, I logged in as an admin on my ownn club website and found that the entire proton.me domain has been blocked by at least one club and is therefore on the master black list that most clubs use by default. Proton is a legitimate email provider and there could be real inquiries coming from people using this domain. We have 5 members in our district with proton emails. I found a support thread from 8 months ago reporting an issue with a club member not being able to email their fellow club members and suspect this might have been the root cause (a specific whitelist entry for that member resolved the problem). Is there a way for the admin team to remove the blanket @proton.me black list or contact the club(s) who added it to ask them to remove it? I am concerned that clubs may be missing out on legitimate inquiries.

Whoever had it blocked removed proton.me. It could come back at anytime.
Blacklist only works on incoming email.
Best to add the emails to your district whitelist.

Our district doesn't actually use Free Toast Host for our district website. I can certainly notify all of our clubs to add it back to their whitelist, but that won't solve the issue for all the other clubs and districts around the world. Given that this was such a blanket blacklist, I was hoping there would be a way for you to undo it across the board (or at least figure out who added it and ask them to remove that blacklist (and only blacklist the specific emails that caused them to blacklist it in the first place).

We do not interfere with what a club decides to block. You have been given the available work arounds.