Using Mailgun with NextAuth for magic link signins yields ‘535 Authentication failed.’ Here’s a simplified config:
export default require('authModule')({server: {host: process.env.SMTP_HOST, port: 587}});
I have dealt with this exact issue and eventually discovered that the error was not directly with the integration itself, but with the credentials used for Mailgun. I overlooked the fact that the Mailgun SMTP username is different from the API key usually used in the HTTP API. In my case, setting the correct username and password in the environment variables resolved the error. Additionally, I found that some SMTP ports require TLS configuration which, if omitted, can lead to similar authentication issues. Double-check that all your environment variables are correctly set and that the port settings align with Mailgun’s recommendations for SMTP connections.
In my experience with configuring Mailgun for NextAuth, the ‘535 Authentication failed’ error was often due to overlooked settings beyond just the username and password. I had to delve deeper into the environment variables and ensure that every parameter was exactly as Mailgun specified. I also found that certain ports and security protocols can complicate even small errors in configuration. Verifying the details with a separate SMTP client helped me isolate the incorrect parameter, leading me to adjust my settings until the connection was properly authenticated.
hey, i had a simalar issue once. besides creds, check yer tls settings and your domain info in the env vars. even a wee typo can wreck auth. a recheck fixed it for me!
I encountered a similar problem when integrating Mailgun with NextAuth several months ago. I spent quite some time debugging and discovered that the issue was initially masked by a subtle misconfiguration in the TLS security settings. I was using an environment setup that slightly differed from Mailgun’s recent recommendations. After reviewing their updated documentation and verifying the SMTP credentials using a basic script, the problem resolved itself. I recommend experimenting with test requests and even trying different ports if you suspect a security layer mismatch. Consistency between your environment variables and Mailgun’s current spec is key.
In my experience resolving Mailgun and NextAuth integration issues, reliance solely on credentials can be misleading. I encountered a ‘535 Authentication failed’ error when subtle TLS configurations and network constraints interfered with proper SMTP handshake. Testing the connection externally with a simple SMTP script helped me isolate the issue as a security protocol mismatch rather than a credential error. It is essential to ensure that firewall rules and hosting settings are aligned with Mailgun’s security recommendations. Accurate testing beyond the application context has proven effective and can lead to a successful resolution.