I'll take a look via Firefox on desktop a bit later as everything seems fine through the mobile browser.
Not sure what you're referring to regarding the contact form though?
Encrypting directly with RSA according to PKCS#1 is limited to a maximum of 501 bytes (key modulus - 11 bytes).
Generally RSA is not used to encrypt data directly, instead you encrypt an AES key with RSA then encrypt the data with that key.
https://stackoverflow.com/a/5586652
https://security.stackexchange.com/a/33445
Edit: the messages are from a character limited contact form so it's fine
Encrypting directly with RSA according to PKCS#1 is limited to a maximum of 501 bytes (key modulus - 11 bytes).
Generally RSA is not used to encrypt data directly, instead you encrypt an AES key with RSA then encrypt the data with that key.
https://stackoverflow.com/a/5586652
https://security.stackexchange.com/a/33445
Edit: the messages are from a character limited contact form so it's fine