WhatsApp has stopped the ability to send messages with short urls like wa.me for people who are not registered in your contacts. It is not clear at the moment whether he did this permanently or if this situation will improve after a while.
As a workaround, you need to save numbers in bulk in your contacts. I showed it in detail in the video here.
https://www.youtube.com/watch?v=aUWeO2GMazY
To summarize
- we list destination numbers without country code.
- export phone numbers to google spreadsheet. Make column header phone and download as .csv
- Import the .csv file in the google contacts app.
- export again as vcard by selecting export option
- open the contacts list on your phone and select the import option. Import the vcard file
- After doing these steps, you can send a message to their phone
number.
Remember this is a temporary solution. I hope whatsapp will be restored soon because many people use short urls to send messages