I was recently invited to be a speaker at a conference but it seems rather strange. I had to pay USD 700 for registration. The website is beautiful, and it is organized by this "Longdom Conferences" which apparently works in the production of many other conferences. They insisted that I registered quickly and the contact was through my whatsapp (I provided my phone number when I had to make a pre-registration, but they never mentioned they would contact this way...). When I mentioned the high price for an unknown conference, they kept giving me discounts and insisting that I register soon. Well, there are names of professors from universities all over the world. I checked this "Longdom Conferences" and it is on the recent Dolos List of predatory conferences:
https://www.professeur-alexandre-georges.info/dolos-list
To be honest, I was not even aware this list existed. The conference name is: " New Frontiers in Renewable Energy and Resources" and this is their website:
https://www.longdom.com/euro-renewableenergy
Any advice would be helpful.