Hubspot表单提交返回415 Unsupported Media Type错误排查求助

在WordPress网站中嵌入了一个简单的HTML注册表单，用于提交数据至HubSpot。表单渲染正常，但提交时始终返回415“Unsupported Media Type”错误。

表单HTML代码（已移除id和class属性） #

<form method="POST" enctype="application/x-www-form-urlencoded" accept-charset="UTF-8" novalidate="" action="https://forms.hsforms.com/submissions/v3/public/submit/formsnext/multipart/49109990/6f68eafc-7fb5-46c6-ade6-96a3967e2662">
    <input required="" placeholder="your@email.com" type="email" name="email" inputmode="email" autocomplete="email">
    <input required="" placeholder="First Name" type="text" name="firstname" inputmode="text" autocomplete="given-name">
    <input required="" placeholder="Last Name" type="text" name="lastname" inputmode="text" autocomplete="family-name">
    <button data-slot="button" type="submit" value="Submit">Subscribe</button>
</form>

请求头信息 #

POST /submissions/v3/public/submit/formsnext/multipart/49109990/6f68eafc-7fb5-46c6-ade6-96a3967e2662 HTTP/3
Host: forms.hsforms.com
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:137.0) Gecko/20100101 Firefox/137.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate, br, zstd
Referer: https://integrate-ed.org/
Content-Type: application/x-www-form-urlencoded
Content-Length: 62
Origin: https://integrate-ed.org
DNT: 1
Connection: keep-alive
Cookie: _cfuvid=j2i2MKFliRHQZNCjR2ulXTUv7VMaTb7yvk3oJUEp_T4-1744995552742-0.0.1.1-604800000; __cf_bm=GrlGyMDPZTtk1bubUCfnxfuDbgEMV1inx5d.y18S4tk-1745001493-1.0.1.1-hqL0bqpkQlz0tXocL5TTSg1zAcCjOja0eOkTKV2vM8kE_QhTlC0_BJe.b9NmaJme01hSDU39dOUP7ZhSS_.Ih8Hvw5sOuB2S49DnSNHNYWU
Upgrade-Insecure-Requests: 1
Sec-Fetch-Dest: iframe
Sec-Fetch-Mode: navigate
Sec-Fetch-Site: cross-site
Sec-Fetch-User: ?1
Priority: u=6

请求负载 #

email=test_german%40nowhere.com&firstname=Test&lastname=German

已尝试的解决方案 #

• 确保Content-Type设置为"application/x-www-form-urlencoded"（之前未设置）
• 尝试将charset设置为"utf-8"、"utf8"和"iso-8859-1"
• 尝试将Accept设置为"application/x-www-form-urlencoded"、"text/plain"、"utf-8"、"utf8"、"text/html;charset=iso-8859-1"和"/"

响应头信息 #

POST
https://forms.hsforms.com/submissions/v3/public/submit/formsnext/multipart/49109990/6f68eafc-7fb5-46c6-ade6-96a3967e2662
[HTTP/3 415  164ms]

POST
    https://forms.hsforms.com/submissions/v3/public/submit/formsnext/multipart/49109990/6f68eafc-7fb5-46c6-ade6-96a3967e2662
Status
415
VersionHTTP/3
Transferred1.23 kB (237 B size)
Referrer Policystrict-origin-when-cross-origin
DNS ResolutionDNS over HTTPS
Blocking
Enhanced Tracking Protection
This URL matches a known tracker and it would be blocked with Content Blocking enabled.

HTTP/3 415 

date: Fri, 18 Apr 2025 18:45:02 GMT
content-type: text/html;charset=iso-8859-1
cache-control: max-age=0, no-cache, no-store
access-control-allow-origin: https://integrate-ed.org
access-control-allow-methods: OPTIONS, POST
access-control-allow-headers: *
access-control-allow-credentials: false
vary: origin
x-content-type-options: nosniff
x-envoy-upstream-service-time: 2
x-evy-trace-route-service-name: envoyset-translator
x-evy-trace-virtual-host: all
x-hubspot-correlation-id: d5fa1e17-d5a8-406e-802f-abcbcef0ec12
x-evy-trace-served-by-pod: iad02/star-hubspot-td/envoy-proxy-5c76648889-lj6zk
x-evy-trace-listener: listener_https
x-evy-trace-route-configuration: listener_https/all
x-request-id: d5fa1e17-d5a8-406e-802f-abcbcef0ec12
cf-cache-status: DYNAMIC
priority: u=6,i=?0
strict-transport-security: max-age=31536000; includeSubDomains; preload
server: cloudflare
cf-ray: 9326511f585f6204-ORD
alt-svc: h3=":443"; ma=86400
server-timing: cfExtPri

Accept
    text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Encoding
    gzip, deflate, br, zstd
Accept-Language
    en-US,en;q=0.5
Connection
    keep-alive
Content-Length
    62
Content-Type
    application/x-www-form-urlencoded
Cookie
    _cfuvid=j2i2MKFliRHQZNCjR2ulXTUv7VMaTb7yvk3oJUEp_T4-1744995552742-0.0.1.1-604800000; __cf_bm=GrlGyMDPZTtk1bubUCfnxfuDbgEMV1inx5d.y18S4tk-1745001493-1.0.1.1-hqL0bqpkQlz0tXocL5TTSg1zAcCjOja0eOkTKV2vM8kE_QhTlC0_BJe.b9NmaJme01hSDU39dOUP7ZhSS_.Ih8Hvw5sOuB2S49DnSNHNYWU
DNT
    1
Host
    forms.hsforms.com
Origin
    https://integrate-ed.org
Priority
    u=6
Referer
    https://integrate-ed.org/
Sec-Fetch-Dest
    iframe
Sec-Fetch-Mode
    navigate
Sec-Fetch-Site
    cross-site
Sec-Fetch-User
    ?1
Upgrade-Insecure-Requests
    1
User-Agent
    Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:137.0) Gecko/20100101 Firefox/137.0

核心问题分析 #

你的表单提交URL包含multipart路径段，这表示HubSpot期望接收**multipart/form-data格式**的请求，但你的表单设置的enctype是application/x-www-form-urlencoded，两者格式不匹配，直接触发415错误。

解决方案 #

有两种修复方式，任选其一即可：

1. 修改表单的enctype：将表单的enctype改为multipart/form-data，匹配HubSpot的multipart端点要求：

<form method="POST" enctype="multipart/form-data" accept-charset="UTF-8" novalidate="" action="https://forms.hsforms.com/submissions/v3/public/submit/formsnext/multipart/49109990/6f68eafc-7fb5-46c6-ade6-96a3967e2662">
    <input required="" placeholder="your@email.com" type="email" name="email" inputmode="email" autocomplete="email">
    <input required="" placeholder="First Name" type="text" name="firstname" inputmode="text" autocomplete="given-name">
    <input required="" placeholder="Last Name" type="text" name="lastname" inputmode="text" autocomplete="family-name">
    <button data-slot="button" type="submit" value="Submit">Subscribe</button>
</form>

2. 更换为非multipart端点：由于你的表单没有文件上传需求，直接移除URL中的multipart路径段，使用标准表单提交端点，保持application/x-www-form-urlencoded的enctype即可：

<form method="POST" enctype="application/x-www-form-urlencoded" accept-charset="UTF-8" novalidate="" action="https://forms.hsforms.com/submissions/v3/public/submit/formsnext/49109990/6f68eafc-7fb5-46c6-ade6-96a3967e2662">
    <input required="" placeholder="your@email.com" type="email" name="email" inputmode="email" autocomplete="email">
    <input required="" placeholder="First Name" type="text" name="firstname" inputmode="text" autocomplete="given-name">
    <input required="" placeholder="Last Name" type="text" name="lastname" inputmode="text" autocomplete="family-name">
    <button data-slot="button" type="submit" value="Submit">Subscribe</button>
</form>

补充说明 #

HubSpot的v3表单提交接口分为两类：

• /multipart/路径：专为带文件上传的表单设计，强制要求请求格式为multipart/form-data
• 标准路径：处理普通键值对表单数据，支持application/x-www-form-urlencoded或application/json格式

你的请求仅包含普通文本字段，无需使用multipart端点，第二种方案更贴合需求。

内容的提问来源于stack exchange，提问作者Jennifer G.